DTC B1236

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 DTC Descriptor DTC B1236 Backup Lamps Control Circuit Symptom Byte Information: Symptom Byte List Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performanc
Backup Lamp Control	B1236 11 or 1	B1236 13 or 1	B1236 12 or 1	B1236 00 or B1A62 4A,82, 86
1. Rearview Camera Display = Malfunction

Circuit/System Description When the transmission is placed into REVERSE, a signal is sent to the Radio indicating that camera operation is requested. The rearview camera sends video information to the radio through a coax cable. The coax cable also provides power from the Radio to the rearview camera. Conditions for Running the DTC Engine running Transmission in R Conditions for Setting the DTC The video signal from the rearview camera has not been received by the Radio or is frozen for 2.5  s. Action Taken When the DTC Sets The Radio stores the DTC in memory. A service message may be displayed on the driver information center of info display module. Conditions for Clearing the DTC The condition responsible for setting the DTC no longer exists. A history DTC will clear once 100 malfunction-free ignition cycles have occurred. Diagnostic Aids A poor video image can be caused by ice, snow, and mud buildup on the lens of the rearview camera. Also, extreme lighting conditions can affect performance, such as operating in the dark or with bright sunlight shining on the camera. Extreme high or low temperatures can also affect the image quality. An open in the shield of the video signal circuit can also cause a distorted screen. An open in the backup lamp control circuit, defective backup lamps, or incorrect/aftermarket backup lamps can cause erratic circuit behavior such as unwanted voltage on circuit when vehicle is no longer in REVERSE. The rear vision image display remaining active after the vehicle is shifted out of REVERSE can also be an indication of backup lamp control circuit issues. Reference Information Schematic Reference Image Display Camera Schematics Connector End View Reference Master Electrical Component List Description and Operation Rear Vision Camera Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References for scan tool information Special Tools EL-52552 COAX FAKRA CABLE ADAPTER KIT Equivalent regional tools: Special Tools Circuit/System Verification

1. Verify A22 Radio Control displays infotainment system information properly. ⇒ If infotainment system information does not display properly Refer to Symptoms - Entertainment. ⇓ If infotainment system information displays properly
2. Ignition » On / Vehicle » In Service Mode
3. Verify DTC B1236 is not set in any other module. ⇒ If the DTC is set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle. ⇓ If the DTC is not set
4. Engine running, parking brake applied, transmission in REVERSE.

Note

An open in the backup lamp control circuit, defective backup lamps, or incorrect/aftermarket backup lamps can cause erratic circuit behavior such as unwanted voltage on circuit when vehicle is no longer in REVERSE. The rear vision image display remaining active after the vehicle is shifted out of REVERSE can also be an indication of backup lamp control circuit issues.

5. Verify the backup lamps are illuminated. ⇒ If the backup lamps are not illuminated Refer to Backup Lamps Malfunction. ⇓ If the backup lamps are illuminated
6. Engine running, parking brake applied, transmission in REVERSE.

Note

A poor quality image is an image that has flickering, blinking, excessively blue/yellow hue, and/or fog/haze such that it obstructs the driver’s view out the rear of the vehicle.

7. Verify a clear rear vision image is displayed on the A22 Radio Control . ⇒ If a clear image is not displayed Refer to Circuit/System Testing. ⇓ If a clear image is displayed
8. All OK. Circuit/System Testing
9. Ignition/Vehicle & All vehicle systems » Off
10. Disconnect the electrical connector: X2 @ A11 Radio
11. Apply the parking brake.
12. Engine Running & Transmission in Reverse
13. Verify a test lamp turns On between the test points: Control circuit terminal 13 & Ground ⇒ If the test lamp does not turn On 5.1. Ignition/Vehicle » Off & Remove » Test lamp 5.2. Test for less than 2 Ω between the test points: Control circuit terminal 13 @ Component harness & The other end of the circuit ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇓ If less than 2 Ω 5.3. Test for infinite resistance between the test points: Control circuit terminal 13 & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇒ If infinite resistance » Test or replace the component: K219 Exterior Lighting Control Module ⇓ If the test lamp turns On
14. Ignition/Vehicle & All vehicle systems » Off
15. Disconnect the electrical connector: X5 @ A11 Radio

Note

Before testing the coax cable, check the cable’s exterior for being pinched, cut, damaged, or having loose connections at the components, all of which can cause reception issues.

8. Disconnect the electrical connector: X3 @ K157 Video Processing Module
9. Locate the appropriate pinout adapter and load test loop adapter from EL-52552 COAX FAKRA Cable Adaptor Kit.
10. Connect the 2 adapters together, measure and record the resistance between the terminals at the pinout adapter.
11. Disconnect the 2 adapters and connect each one to the appropriate end of the coax cable.
12. At the pinout adapter test terminals, measure the total resistance of the coax cable loop including the connected load test adapter. ⇒ If not within 5 Ω of the reading from step 10. Replace the coax cable ⇓ If within 5 Ω of the reading from step 10.
13. Replace the component: K157 Video Processing Module
14. Apply the parking brake.
15. Engine Running Transmission in Reverse
16. Verify DTC B1236 is not set. ⇒ If the DTC is set Replace the component: A11 Radio ⇓ If the DTC is not set
17. All OK. Component Testing

Caution

Refer to Test Probe Caution

Note

Before testing the coax cable, check the cable exterior for being pinched, cut, damaged, or having loose connections at the components, which can cause reception issues. To prevent false readings when testing the center coax terminals, use care not to ground the test probe on the outer housing/shield. Coax Cable Test

1. Connect appropriate EL-52552 pinout tool to Coax Cable
2. Test for less than 5 Ω between the coax cable center terminal end to end. ⇒ If 5 Ω or greater Replace the coax cable. ⇓ If less than 5 Ω
3. Test for greater than 5 Ω between the coax cable outer shield end to end. ⇒ If 5 Ω or greater Replace the coax cable. ⇓ If less than 5 Ω
4. Test for infinite resistance between the coax cable center terminal and the coax cable outer shield. ⇒ If less than infinite resistance Replace the coax cable. ⇓ If infinite resistance
5. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair procedure. Rearview Driver Information Camera Replacement Control Module References for control module replacement, programming, and setup.