Battery Electrical Drain_Parasitic Load Test

Battery Electrical Drain/Parasitic Load Test 12 V Battery The following procedure is for the 12 V battery only. Diagnostic Instructions Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach. Diagnostic Procedure Instructions provides an overview of each diagnostic category. Circuit/System Description Components most likely to cause a parasitic draw on the vehicles battery are switches, relays, and control modules. After the ignition is turned OFF the control modules will begin to go to sleep (shut OFF). All control modules do not go to sleep at the same time, some may take up to 30 minutes or longer after turning the ignition off before going to sleep e.g. RAP or IRAP. Other components such as EVAP, HVAC afterblow, EV Battery Heater/Coolers, OnStar and keyless entry control modules (approach detection in keyless access vehicles) etc. may periodically wake up then go back to sleep. These are all normal conditions, use of a DMM set to Min/Max may help identify the normal types of spikes in the parasitic draws . Diagnostic Aids Active Draws If the battery voltage is interrupted by removing fuses, relays, module or component connectors, or disconnecting the battery may cause the condition to clear or reset. To prevent a loss of power when disconnecting the battery install the EQPMSK6211 Battery Booster Pack or equivalent to the positive and negative battery cables prior disconnecting it to prevent a loss of voltage. Verify no aftermarket accessories are installed or connected to the Auxiliary Power Ports, Audio Ports, or DLC. e.g. insurance snapshot or tracking devices. On Some Vehicles the Auxiliary Power Ports can have B+ at all times (not controlled by RAP) by relocating the fuse in the fuseblock. Aftermarket accessories installed into the courtesy lamp circuit may cause the inadvertent power timer in the K9 Body Control Module (BCM) to keep resetting. This may cause the BCM to remain awake and cause a current drain on the battery. Verify that the battery and charging system are operating correctly. Refer to Battery Charging and Charging System Test. An engine off natural vacuum evaporative test can occur if the Engine Control Module (ECM) determines the drive cycle has met the appropriate criteria immediately after key off. The ECM will stay awake and the vent solenoid will stay energized for up to 45 min. The typical current draw for this is approximately 1 A. The K9 Body Control Module has discrete input and output terminals to control the vehicle’s body functions. The K9 Body Control Module is wired to the High Speed GMLAN bus, Low Speed GMLAN bus and multiple Local Interconnect Network (LIN) buses and acts as a gateway between them. The various K9 Body Control Module input and output circuits are illustrated in the corresponding functional areas on the K9 Body Control Module electrical schematics. The K9 Body Control Module functions as the power mode master. The ignition switch is a low current switch with multiple discrete ignition switch signals to the power mode master for determining the power mode that will be sent over the serial data circuits to the other devices that need this information; the power mode master will activate relays and other direct outputs of the power mode master as needed. Refer to Power Mode Description and Operation for a complete description of power mode functions. The K9 Body Control Module functions as a gateway or translator. The purpose of the gateway is to translate serial data messages between the High Speed GMLAN bus and the Low Speed GMLAN bus for communication between the various devices. The gateway will interact with each network according to that network’s transmission protocol. All communication between the K9 Body Control Module and a scan tool is done through the primary High Speed GMLAN bus. Generation 5 and prior OnStar module does can “wake up” every 10 minutes for the first 48 hours, for Generation 6 and later the current draw is very low, less than 40 mA, the OnStar system is left in that state for up to the first 48 h. a parasitic draw of up to 40 mA with an occasional spike as high as 80 mA for the first 48 hours is normal. Refer to OnStar Description and Operation OnStar Sleep Cycle. Some automatic climate control systems can remain in a semi awake state for up to three hours, actual draw amounts vary by vehicle platform but are typically not greater than 50  mA. An extremely low mA current level is consumed by the body control module for monitoring purposes, actual system wake up occurs when the fobs for the vehicle are activated or approach is detected on keyless access vehicles. Other devices that operate on the same remote keyless entry frequency, such as the tire pressure monitoring sensors and other vehicle Fobs in the vicinity, may cause the body control module to have a 100 mA spike. These spikes are normal and occur too briefly to have a significant effect on battery drain. If an excessive current draw is not present during initial testing, continue periodic testing over a 1–2 hour period to see if the current draw increases and stays above an unacceptable level.

Note

The battery specification listed below is a generic specification. Refer to the label on the original battery when testing the battery. The battery run down time will vary depending on the batteries reserve capacity. If the reserve capacity is higher, then the battery run down time may be longer. If the reserve capacity is lower, then the battery run down time may be shorter. The graph below indicates roughly how many days a 690 cold cranking amperage battery with a 110 min. reserve capacity starting at 80 percent state of charge will last with a constant current draw until it reaches 50 percent state of charge. Differences in battery reserve capacity and temperature will affect the results.

Current Drain	Days

Current Drain	Days

Intermittent Draws The Battery Draw Customer Verification Worksheet may be helpful isolating or duplicating the customers concern CCVS - Battery Draw When diagnosing an intermittent battery draw, if the battery voltage is interrupted by removing fuses, relays, module or component connectors, or disconnecting the battery may cause the condition to clear or reset. To prevent a loss of power when disconnecting the battery install the EQPMSK6211 Battery Booster Pack or equivalent to the positive and negative battery cables prior disconnecting it to prevent a loss of voltage. Verify no aftermarket accessories are installed or connected to the Auxiliary Power Ports, Audio Ports, or DLC. e.g. insurance snapshot or tracking devices. On Some Vehicles the Auxiliary Power Ports can have B+ at all times (not controlled by RAP) by relocating the fuse in the fuseblock. Rule out customer driving habits such as regular short trips that do not allow enough time to properly charge the battery. Refer to Battery Description and Operation. Verify that the battery and charging system are operating correctly. Refer to Battery Charging and Charging System Test. A battery discharging for no apparent reason while the vehicle is parked can be caused by an intermittent draw, such as a module waking up, or a continuous draw, such as a dome light or stuck relay. An engine off natural vacuum evaporative test can occur if the Engine Control Module (ECM) determines the drive cycle has met the appropriate criteria immediately after key off. The ECM will stay awake and the vent solenoid will stay energized for up to 45 min. The typical current draw for this is approximately 1 A. The K9 Body Control Module has discrete input and output terminals to control the vehicle’s body functions. The K9 Body Control Module is wired to the High Speed GMLAN bus, Low Speed GMLAN bus and multiple Local Interconnect Network (LIN) buses and acts as a gateway between them. The various K9 Body Control Module input and output circuits are illustrated in the corresponding functional areas on the K9 Body Control Module electrical schematics. The K9 Body Control Module functions as the power mode master. The ignition switch is a low current switch with multiple discrete ignition switch signals to the power mode master for determining the power mode that will be sent over the serial data circuits to the other devices that need this information; the power mode master will activate relays and other direct outputs of the power mode master as needed. Refer to Power Mode Description and Operation for a complete description of power mode functions. The K9 Body Control Module functions as a gateway or translator. The purpose of the gateway is to translate serial data messages between the High Speed GMLAN bus and the Low Speed GMLAN bus for communication between the various devices. The gateway will interact with each network according to that network’s transmission protocol. All communication between the K9 Body Control Module and a scan tool is done through the primary High Speed GMLAN bus. Generation 5 and prior OnStar module does can “wake up” every 10 minutes for the first 48 hours, for Generation 6 and later the current draw is very low, less than 40 mA, the OnStar system is left in that state for up to the first 48 h. a parasitic draw of up to 40 mA with an occasional spike as high as 80 mA for the first 48 hours is normal. Refer to OnStar Description and Operation OnStar Sleep Cycle. Some automatic climate control systems can remain in a semi awake state for up to three hours, actual draw amounts vary by vehicle platform but are typically not greater than 50  mA. An extremely low mA current level is consumed by the body control module for monitoring purposes, actual system wake up occurs when the fobs for the vehicle are activated or approach is detected on keyless access vehicles. Other devices that operate on the same remote keyless entry frequency, such as the tire pressure monitoring sensors and other vehicle Fobs in the vicinity, may cause the body control module to have a 100 mA spike. These spikes are normal and occur too briefly to have a significant effect on battery drain. If an excessive current draw is not present during initial testing, continue periodic testing over a 1–2 hour period to see if the current draw increases and stays above an unacceptable level.

Note

The battery specification listed below is a generic specification. Refer to the label on the original battery when testing the battery. The battery run down time will vary depending on the batteries reserve capacity. If the reserve capacity is higher, then the battery run down time may be longer. If the reserve capacity is lower, then the battery run down time may be shorter. The graph below indicates roughly how many days a 690 cold cranking amperage battery with a 110 min. reserve capacity starting at 80 percent state of charge will last with a constant current draw until it reaches 50 percent state of charge. Differences in battery reserve capacity and temperature will affect the results.

Current Drain	Days

Reference Information Schematic Reference Control Module References Connector End View Reference Master Electrical Component List Electrical Information Reference Circuit Testing Testing for Intermittent Conditions and Poor Connections Connector Repairs Wiring Repairs Scan Tool Reference Control Module References for scan tool information Special Tools EL 38758 Parasitic Draw Test Switch For equivalent regional tools, refer to Special Tools. Circuit/System Verification

Note

Most vehicle systems will go into the initial sleep cycle after 10 min, with periodic normal wake up cycles that will occur for approximately 1 s, it can take up to 2 hours before all systems powers down completely depending on make model or year. Typically a vehicle will not have more than 50 mA parasitic draw during the initial power sleep cycle. Closing the doors, hood, trunk/liftgate, glove compartments, and console switches/ajar switches are closed while leaving the them open is recommended, this allows the vehicle systems to perform in a “doors/hood/trunk/liftgate closed” mode while allowing access to the vehicle components that need to be accessed for testing without waking the vehicle back up. Locking doors will arm the vehicle content theft deterrent system if equipped. Failure to arm the system may cause a theft system fault to not be present during testing. If the vehicle is equipped with intrusion detection, the vehicle will activate full content theft alarm (vehicle wake up with siren and/or horn activation and exterior lighting cycling) when entering the vehicle. There are many things that can prevent the vehicle from completely going to sleep and passing the parasitic draw test. Make sure all the conditions listed below are met before performing the parasitic current draw test. – Ignition OFF – On Some VIP vehicles if the EBCM detects wheel movement it can wake up and apply the electronic parking brake. – Key out of the ignition switch – when not equipped with keyless access and start. Transmitter (Key FOB) away from vehicle for keyless access equipped vehicles. – Retained Accessory Power OFF – open and close the driver door after ignition OFF – Scan tool not communicating with a vehicle control module – in some cases it may need to be disconnected from the DLC – All doors, hood, trunk/liftgate, glove compartments, and console switches, latches and ajar switches are closed. – Head lamps OFF – auto head lamps disabled. – Any delay lighting OFF. – If equipped with an underhood lamp disable it. On vehicles will disable the underhood lamp when the hood latch is closed – If equipped with HVAC Afterblow, after shutting the vehicle off afterblow may cycle on after 30 min for approximately 10 minutes. Starting with some 2021 Model Vehicles afterblow is enabled at the factory and cannot be disabled. – Any accessory that can work with ignition OFF inactive or OFF. On some vehicles the Auxilary Power Ports can be enabled to be on at all times by relocating the fuse in the fuseblock. – Wait 15 min or longer, after all other listed conditions are met Using an Inductive Amp Clamp (Preferred Method)

1. Verify meter operating correctly, refer to the tools owner manual for tool being used,
2. Road test the vehicle in the same manner as the customer does, based on information obtained from the customer verification sheet.
3. Activate all the accessories the vehicle is equipped with, such as the radio, rear seat entertainment, rear defogger, windows, sunroof, front and rear HVAC etc. (operate components through a full cycle) confirm everything is operating correctly and note any components that are not operating correctly.

Note

Zero the meter before connecting the amp clamp and verify the current sensor clamp in the correct orientation (arrow towards the negative battery post).

4. Connect a 50 Amp inductive amp clamp to the negative battery cable that can read down to 1 mA.
5. Ignition OFF.

Note

Open all doors, hood, trunk/liftgate, glove compartments, and console etc to gain access to all components and fuse blocks, manually close all switches, latches and ajar switches are closed.

6. Ignition off, exit the vehicle following the same manner that the customer does, based on information obtained from the customer verification sheet. CCVS - Battery Draw

Note

Intermittent momentary module wake ups may be normal. (Typically, after 20 Minutes, but may take longer)

7. Allow all modules and components to go to sleep.
8. Verify there is less than 40 mA of parasitic current drain. ⇒ If greater than the specified range, refer to Circuit/System Testing. ⇓ If less than the specified range
9. The condition may be an intermittent fault and is currently not present. Perform additional road test or repeat customer scenario to attempt to duplicate the draw Alternate Method for Vehicles with Battery Sensor Module

Warning

Refer to Battery Disconnect Warning.

Caution

When a fused jumper wire or digital multimeter is connected to the test switch terminals, always turn the test switch ON before opening any access door, turning the ignition on, or turning any accessory on. This is to prevent damaging the jumper wire or digital multimeter fuse.

1. Verify meter operating correctly, refer to the tools owner manual for tool being used,

Note

When diagnosing an intermittent battery draw, if the battery voltage is interrupted by disconnecting the battery, fuses relays,componet or module connectors may cause the condition to clear. The switch knob on the EL 38758 switch is marked ON and OFF. When the switch knob is in the ON position, the circuit is closed and electrical current will pass through the switch. When the switch knob is in the OFF position, the circuit is open and electrical current will not pass through the switch.

2. Connect the EQPMSK6211 Battery Booster Pack or equivalent to the Battery positive and negative jump start posts prior to disconnecting the negative battery cable to prevent a loss of voltage which could reset or clear an intermittent draw.

Note

Intermittent momentary module wake ups may be normal. (Typically, after 20 Minutes, but may take longer)

3. Allow all modules and components to go to sleep.

Battery Electrical Drain_Parasitic Load Test — figure 1

4. Connect a 10 A fused jumper wire between the Battery Negative post clamp and the other end of the Negative Battery Cable.

Battery Electrical Drain_Parasitic Load Test — figure 2

5. Remove the Current sensor stud nut and remove the negative cable from the Battery Sensor Module.
6. Check the fuse in the jumper wire. The fuse should be OK. ⇒ If the jumper wire fuse is blown, the vehicle has an Active excessive parasitic draw. Refer to Circuit/System Testing ⇓ If the jumper wire fuse is not blown,
7. Disconnect the the EQPMSK6211 Battery Booster Pack or equivalent

Battery Electrical Drain_Parasitic Load Test — figure 3

8. Verify there is less than 40 mA of parasitic current drain. ⇒ If greater than the specified range, refer to Circuit/System Testing. ⇓ If less than the specified range
9. Reconnect the Battery Negative Battery Cable to the Battery Sensor Module.
10. Road test the vehicle in the same manner as the customer does, based on information obtained from the customer verification sheet. CCVS - Battery Draw
11. Activate all the accessories the vehicle is equipped with, such as the radio, rear seat entertainment, rear defogger, windows, sunroof, front and rear HVAC etc. (operate components through a full cycle) confirm everything is operating correctly and note any components that are not operating correctly.

Note

Open all doors, hood, trunk/liftgate, glove compartments, and console etc to gain access to all components and fuse blocks, manually close all switches, latches and ajar switches are closed.

12. Ignition off, exit the vehicle following the same manner that the customer does, based on information obtained from the customer verification sheet.

Note

When diagnosing an intermittent battery draw, if the battery voltage is interrupted by disconnecting the battery, fuses relays,componet or module connectors may cause the condition to clear. The switch knob on the EL 38758 switch is marked ON and OFF. When the switch knob is in the ON position, the circuit is closed and electrical current will pass through the switch. When the switch knob is in the OFF position, the circuit is open and electrical current will not pass through the switch.

13. Connect the EQPMSK6211 Battery Booster Pack or equivalent to the Battery positive and negative jump start posts prior to disconnecting the negative battery cable to prevent a loss of voltage which could reset or clear an intermittent draw.

Note

Intermittent momentary module wake ups may be normal. (Typically, after 20 Minutes, but may take longer)

14. Allow all modules and components to go to sleep.

15. Connect a 10 A fused jumper wire between the Battery Negative post clamp and the other end of the Negative Battery Cable.

16. Remove the Current sensor stud nut and remove the negative cable from the Battery Sensor Module.

17. Check the fuse in the jumper wire. The fuse should be OK. ⇒ If the jumper wire fuse is blown, the vehicle has an Active excessive parasitic draw. Refer to Circuit/System Testing ⇓ If the jumper wire fuse is not blown,

18. Disconnect the the EQPMSK6211 Battery Booster Pack or equivalent

19. Verify there is less than 40 mA of parasitic current drain. ⇒ If greater than the specified range, refer to Circuit/System Testing. ⇓ If less than the specified range

20. The condition may be an intermittent fault and is currently not present. Perform additional road test, repeat customer scenario per the Battery Draw customer verification sheet to attempt to duplicate the draw. Alternate Method for Vehicles without a Battery Sensor Module Using the EL 38758 Parasitic Draw Test Switch

Warning

Refer to Battery Disconnect Warning.

Caution

When a fused jumper wire or digital multimeter is connected to the test switch terminals, always turn the test switch ON before opening any access door, turning the ignition on, or turning any accessory on. This is to prevent damaging the jumper wire or digital multimeter fuse.

1. Verify meter operating correctly, refer to the tools owner manual for tool being used,

Note

When diagnosing an intermittent battery draw, if the battery voltage is interrupted by disconnecting the battery, fuses relays,componet or module connectors may cause the condition to clear. The switch knob on the EL 38758 switch is marked ON and OFF. When the switch knob is in the ON position, the circuit is closed and electrical current will pass through the switch. When the switch knob is in the OFF position, the circuit is open and electrical current will not pass through the switch.

2. Connect the EQPMSK6211 Battery Booster Pack or equivalent to the Battery positive and negative jump start posts prior to disconnecting the negative battery cable to prevent a loss of voltage which could reset or clear an intermittent draw.
3. Ignition OFF, disconnect the battery negative cable from the battery. Refer to Battery Negative Cable Disconnection and Connection.
4. Turn the EL 38758 switch knob to the OFF position.
5. Install the male end of the EL 38758 switch to the battery ground terminal.
6. Install the battery negative cable to the female end of the EL 38758 switch.
7. Turn the EL 38758 switch knob to the ON position.
8. Disconnect the EQPMSK6211 Battery Booster Pack or equivalent.

Note

Intermittent momentary module wake ups may be normal. (Typically, after 20 Minutes, but may take longer)

9. Allow all modules and components to go to sleep.
10. Connect a 10 A fused jumper wire to the test switch tool terminals.
11. Turn the EL 38758 switch knob to the OFF position. The current now flows through the jumper wire.
12. Check the fuse in the jumper wire. The fuse should be OK. ⇒ If the jumper wire fuse is blown, the vehicle has an Active excessive parasitic draw. Refer to Circuit/System Testing ⇓ If the jumper wire fuse is not blown,
13. Turn the EL 38758 switch knob to the ON position. Remove the fused jumper wire.
14. Connect a DMM set to the 10  A DC scale between the test switch tool terminals.
15. Turn the EL 38758 switch knob to the OFF position. The current now flows through the DMM.
16. Verify there is less than 40 mA of parasitic current drain. ⇒ If greater than the specified range, refer to Circuit/System Testing. ⇓ If less than the specified range
17. Turn the EL 38758 switch knob to the OFF position.
18. Road test the vehicle in the same manner as the customer does, based on information obtained from the customer verification sheet. CCVS - Battery Draw
19. Activate all the accessories the vehicle is equipped with, such as the radio, rear seat entertainment, rear defogger, windows, sunroof, front and rear HVAC etc. (operate components through a full cycle) confirm everything is operating correctly and note any components that are not operating correctly.

Note

Open all doors, hood, trunk/liftgate, glove compartments, and console etc to gain access to all components and fuse blocks, manually close all switches, latches and ajar switches are closed.

20. Ignition off, exit the vehicle following the same manner that the customer does, based on information obtained from the customer verification sheet.

Note

Intermittent momentary module wake ups may be normal. (Typically, after 20 Minutes, but may take longer)

21. Allow all modules and components to go to sleep.
22. Connect a 10 A fused jumper wire to the test switch tool terminals.
23. Turn the EL 38758 switch knob to the OFF position. The current now flows through the jumper wire.
24. Check the fuse in the jumper wire. The fuse should be OK. ⇒ If the jumper wire fuse is blown, refer to Circuit/System Testing. ⇓ If the jumper wire fuse is not blown,
25. Turn the EL 38758 switch knob to the ON position. Remove the fused jumper wire.
26. Connect a DMM set to the 10  A DC scale between the test switch tool terminals.
27. Turn the EL 38758 switch knob to the OFF position. The current now flows through the DMM.
28. Verify there is less than 40 mA of parasitic current drain. ⇒ If greater than the specified range, refer to Circuit/System Testing. ⇓ If less than the specified range
29. The condition may be an intermittent fault and is currently not present. Perform additional road test, repeat customer scenario per the Battery Draw customer verification sheet to attempt to duplicate the draw. Circuit/System Testing

Note

Do not test for a voltage drop at the Junction Block Studs without wiring or cables attached to it. It will result in the DVOM providing a false reading.

Battery Electrical Drain_Parasitic Load Test — figure 4

Battery Junction Block Voltage Drop Example

Note

The Leg of the Battery Junction Block with the highest draw or voltage drop is likely to be the source of the excessive parasitic draw.

1. If the equipped with a battery Junction block and if it is accessible, utilize and inductive amp clamp or perform a voltage drop test between the battery positive post and each leg of the battery junction block to help determine which fuse block is containing the draw. ⇒ If a Parasitic Draw has not been isolated in Step 1.

Battery Electrical Drain_Parasitic Load Test — figure 5

Standard Fuse Voltage Drop Test Example

Battery Electrical Drain_Parasitic Load Test — figure 6

Battery Electrical Drain_Parasitic Load Test — figure 7

Note

The center of the fuse is the supply voltage for both sides of the fuse. Micro 3 Fuse Voltage Drop Test Example

Note

Some fuses that may have an initial voltage drop then drop off, and some fuses that always have a nominal draw going to components that supply memory retention is normal. 1.1. Use a DMM set to mV scale and perform a voltage drop across each fuse excluding J-Case type fuses (ignore negative readings) one at a time to determine the fuse that is causing the parasitic draw using the tables and selecting the appropriate Fuse type. Refer to: Parasitic Draw Reference Table ⇓ If a Parasitic Draw has been Isolated in Step 1 1.2. Go to the fuse block that the draw has been isolated to.

Standard Fuse Voltage Drop Test Example

Note

The center of the fuse is the supply voltage for both sides of the fuse. Micro 3 Fuse Voltage Drop Test Example

Note

Some fuses that may have an initial voltage drop then drop off, and some fuses that always have a nominal draw going to components that supply memory retention is normal. 1.3. Use a DMM set to mV scale and perform a voltage drop across each fuse excluding J-Case type fuses (ignore negative readings) one at a time to determine the fuse that is causing the parasitic draw using the tables and selecting the appropriate Fuse type. Refer to: Parasitic Draw Reference Table ⇒ If a voltage drop is found

Note

Do NOT remove any fuses as it may cause the draw to go away and may not return. If the draw is isolated to a fuse that supplies voltage to more than one component, disconnect the components one at a time until the draw is gone. Refer to Power Distribution Schematics to diagnose exactly which circuit of the suspect system is causing the high parasitic drain. ⇓ If a voltage drop is not found

2. Verify an excessive current draw is not present by removing each remaining J-Case fuse(s), circuit breaker(s), relay(s), components and modules one at a time while monitoring the draw to verify it drops to below 40 mA. ⇒ If an excessive parasitic draw is found

Note

Do NOT remove any fuses as it may cause the draw to go away and may not return. If the draw is isolated to a fuse that supplies voltage to more than one component, disconnect the components one at a time until the draw is gone. Refer to Power Distribution Schematics to diagnose exactly which circuit of the suspect system is causing the high parasitic drain. ⇓ If an excessive parasitic draw is not found

3. The condition may be an intermittent fault and is currently not present. Stuck switch Stuck relay Control module Perform additional road test, repeat customer scenario per the Battery Draw customer verification sheet to attempt to duplicate the draw, Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Control Module References for control module replacement, programming and setup