Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5501054
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic
System Check - Vehicle
Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis
An overview of each diagnostic category can be found here: Diagnostic Procedure
Instructions
DTC Descriptor
DTC P1029
Fuel Pump Motor Phase U-V-W Circuits
DTC P102A
Fuel Pump Motor Phase U-V-W Circuits Low
DTC P102B
Fuel Pump Motor Phase U-V-W Circuits High
Diagnostic Fault Information
| Circuit |
Short to Ground |
Open/High Resistance |
Short to Voltage |
Control Circuit Shorted to Control Circuit |
| Control — Terminal 1 @ A7 Fuel Tank Fuel Pump Module |
P102A |
P1029 |
P102B |
P102C |
| Control — Terminal 2 @ A7 Fuel Tank Fuel Pump Module |
P102A |
P1029 |
P102B |
P102C |
| Control — Terminal 3 @ A7 Fuel Tank Fuel Pump Module |
P102A |
P1029 |
P102B |
P102C |
Typical Scan Tool Data
Fuel Pump Motor Control Circuit High Test Status
| Circuit |
Short to Ground |
Open |
Short to Voltage |
Control Circuit Shorted to Control Circuit |
| Operating Conditions: Ignition = On Parameter Normal Range: Not Run / Okay |
|
|
|
|
| Control — Terminal 1 |
Not Run / Okay |
Not Run / Okay |
Malfunction |
Not Run / Okay |
| Circuit |
Short to Ground |
Open |
Short to Voltage |
Control Circuit Shorted to Control Circuit |
| Control — Terminal 2 |
Not Run / Okay |
Not Run / Okay |
Malfunction |
Not Run / Okay |
| Control — Terminal 3 |
Not Run / Okay |
Not Run / Okay |
Malfunction |
Not Run / Okay |
Fuel Pump Motor Control Circuit Low Test Status
| Circuit |
Short to Ground |
Open |
Short to Voltage |
Control Circuit Shorted to Control Circuit |
| Operating Conditions: Ignition = On Parameter Normal Range: Not Run / Okay |
|
|
|
|
| Control — Terminal 1 |
Malfunction |
Not Run / Okay |
Not Run / Okay |
Not Run / Okay |
| Control — Terminal 2 |
Malfunction |
Not Run / Okay |
Not Run / Okay |
Not Run / Okay |
| Control — Terminal 3 |
Malfunction |
Not Run / Okay |
Not Run / Okay |
Not Run / Okay |
Fuel Pump Motor Control Circuit Open Test Status
|
Circuit |
Short to Ground |
Open |
Short to Voltage |
Control Circuit Shorted to Control Circuit |
|
|
Operating Conditions: Ignition = On Parameter Normal Range: Not Run / Okay |
|
|
|
|
|
|
Control — Terminal 1 |
Not Run / Okay |
Malfunction |
Not Run / Okay |
Not Run / Okay |
|
|
Control — Terminal 2 |
Not Run / Okay |
Malfunction |
Not Run / Okay |
Not Run / Okay |
|
|
Control — Terminal 3 |
Not Run / Okay |
Malfunction |
Not Run / Okay |
Not Run / Okay |
|
Circuit/System Description
For an overview of the component/system, refer to: Fuel System Description
| Circuit |
Description |
| Control |
The output circuit varies between ground and 12 V. |
| Component |
Description |
| G12 Fuel Pump |
The component has a 3-phase motor. The control module converts the DC voltage from the battery to 3-phase AC to power the motor. |
| K111 Fuel Pump Power Control Module |
The control module K111 supplies the fuel pump with a 3-phase voltage in order to achieve the desired pump speed required for building fuel line pressure. |
Conditions for Running the DTC
P1029
KR73 Ignition Main Relay = On
Fuel Pump Speed = 0 RPM
Frequency the DTC runs = Continuously — After the running conditions are met
P102A, P102B
KR73 Ignition Main Relay = On
Frequency the DTC runs = Continuously — After the running conditions are met
Conditions for Setting the DTC
P1029
Fuel Pump Motor Control Circuit = Open — For greater than 1 s
P102A
Fuel Pump Motor Control Circuit = Short to Ground — For greater than 1 s
P102B
Fuel Pump Motor Control Circuit = Short to Voltage — For greater than 1 s
Actions Taken When the DTC Sets
DTCs listed in the DTC Descriptor category = Type A DTC
Conditions for Clearing the DTC
DTCs listed in the DTC Descriptor category = Type A DTC
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Master Electrical Component List
Electrical Information Reference
Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
Circuit/System Verification
- Ignition » On / Vehicle » In Service Mode
- Verify DTC U18A2 is not set.
⇒ If the DTC is set
Refer to: Diagnostic Trouble Code (DTC) List - Vehicle
⇓ If the DTC is not set
- Verify the scan tool parameter:
Fuel Pump Motor Control Circuit High Test Status = Not Run or Okay
Fuel Pump Motor Control Circuit Low Test Status = Not Run or Okay
Fuel Pump Motor Control Circuit Open Test Status = Not Run or Okay
⇒ If not the specified state
Refer to: Circuit/System Testing
⇓ If the specified state
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the
vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Verify the DTC does not set.
⇒ If the DTC sets
Refer to: Circuit/System Testing
⇓ If the DTC is not set
- All OK.
Circuit/System Testing
- Ignition/Vehicle » Off
- Verify the condition does not exist: Fuel — Contaminated / Poor Quality » Refer to:
Contaminants-in-Fuel Diagnosis
⇒ If a condition exists
Repair or replace as necessary
⇓ If no condition exists
- Ignition/Vehicle & All vehicle systems » Off
- Disconnect the electrical connector: K111 Fuel Pump Power Control Module
- Ignition » On / Vehicle » In Service Mode
- Test for less than 1 V between the test points:
Control circuit terminal 8 & Ground
Control circuit terminal 9 & Ground
Control circuit terminal 24 & Ground
⇒ If 1 V or greater
Repair the short to voltage on the circuit.
⇓ If less than 1 V
- Ignition/Vehicle & All vehicle systems » Off
- Test for infinite resistance between the test points:
Control circuit terminal 8 & Ground
Control circuit terminal 9 & Ground
Control circuit terminal 24 & Ground
⇒ If less than infinite resistance
Repair the short to ground on the circuit.
⇓ If infinite resistance
- Disconnect the electrical connector: A7 Fuel Tank Fuel Pump Module
- Test for less than 2 Ω between the test points:
Control circuit terminal 8 @ Control module harness & Terminal 1 @ Component harness
Control circuit terminal 9 @ Control module harness & Terminal 2 @ Component harness
Control circuit terminal 24 @ Control module harness & Terminal 3 @ Component
harness
⇒ If 2 Ω or greater
Repair the open/high resistance in the circuit.
⇓ If less than 2 Ω
- Replace the component: A7 Fuel Tank Fuel Pump Module
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the
vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Verify the DTC does not set.
⇒ If the DTC sets
Replace the component: K111 Fuel Pump Power Control Module
⇓ If the DTC does not set
- All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair
Verification
Fuel Tank Fuel Pump Module Replacement — A7 Fuel Tank Fuel Pump Module
For control module replacement, programming, and setup refer to: Control Module
References