DTC B171C, B17FE, or B1803

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 B171C Driver Door Lock Motor Unlock Control DTC B1803 Driver Door Unlatch Motor Latch Control Symptom Byte Information: Symptom Byte List Diagnostic Fault Information

Circuit number	Circuit Function	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performan
2679	Control	1	B171C 12, B171C 13	—	—
2681	Control	B1803 11	B1803 12, B1803 13	B1803 12, B1803 13	—
3266	Control	B13DF 11	B171C 12, B171C 13	—	—
1. Left rear door Lock and Unlock function inoperative

Circuit/System Description The K9 Body Control Module provides the control circuit 3266 and control circuit 2679 with voltage and ground to the appropriate lock and unlock control circuits of the door latches. The unlock control circuit of the left rear and driver door latches share a common control circuit 2679. Transitioning of the lock actuators to the lock or unlocked position depends upon which control circuits receive voltage and which control circuits receive ground. Conditions for Running the DTC Ignition » On / Vehicle » In Service Mode Conditions for Setting the DTC B171C 12, B171C 13 2679= Open 3266= Open B1803 11 2681= Short to ground B1803 12, B1803 13 2861= Open or short to voltage Actions Taken When the DTC Sets A23LR Rear Side Door Latch - Left — Lock & Unlock = Inoperative A23LR Rear Side Door Latch - Left — Child lock= Inoperative Child lockout indicator will flash ON and OFF DIC Service Door Latch System— Displayed Conditions for Clearing the DTC A current DTC will clear when the diagnostic runs and passes. A history DTC will clear after 40 consecutive malfunction-free ignition cycles. Reference Information Schematic Reference Door Lock/Indicator Schematics Connector End View Reference Master Electrical Component List Description and Operation Power Door Locks 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 Circuit/System Verification

1. Ignition » On / Vehicle » In Service Mode
2. Operate the component: S13D Door Lock Switch - Driver » Lock Switch & Unlock Switch Verify the component works as specified: A23D Front Side Door Latch-Driver= Lock & Unlock ⇒ If the component does not activate Refer to: Circuit/System Testing — Test 1 ⇓ If all functions work properly
3. Operate the component: S13D Door Lock Switch - Driver » Lock Switch & Unlock Switch Verify the component works as specified: A23LR Rear Side Door Latch - Left = Lock & Unlock ⇒ If the component does not activate Refer to: Circuit/System Testing — Test 2 ⇓ If all functions work properly
4. Engage the child door locks by pressing the child lock switch on the S79D Front Side Door Window Control Switch-Driver Verify the correct operation: Interior Door Handle @ Left Rear Door = Disabled ⇒ If the component does not work as specified Refer to: Circuit/System Testing — Test 2 ⇓ If the component works as specified
5. A fault that is not currently present may have been caused by a intermittent condition. Circuit/System Testing Test 1
6. Ignition/Vehicle » Off
7. Disconnect the electrical connector: A23D Front Side Door Latch-Driver
8. Connect a test lamp between the test points: Control circuit terminal 7 & ground
9. Ignition » On / Vehicle » In Service Mode
10. Operate the component: S13D Door Lock Switch - Driver Verify the test lamp state: Not used= Test lamp Off Lock Switch » Pressed = Test lamp flashes ON and OFF ⇒ If the test lamp is always OFF 5.1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module 5.2. Test for infinite resistance between the control 2681 and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 5.3. Test for less than 2 Ω in the control 2681 end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K9 Body Control Module ⇒ If the test lamp is always ON 5.1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON. 5.2. Test for less than 1 V between the control 2681 and ground. ⇒ If 1 V or greater, repair the short to voltage on the circuit. ⇒ If less than 1 V, replace the K9 Body Control Module ⇓ If the test lamp turns ON and OFF
11. Connect a test lamp between the test points: Control circuit terminal 8 & ground
12. Ignition » On / Vehicle » In Service Mode
13. Operate the component: S13D Door Lock Switch - Driver Verify the test lamp state: Not used= Test lamp Off Unlock» Pressed = Test lamp flashes ON and OFF ⇒ If the test lamp is always OFF 8.1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module 8.2. Test for infinite resistance between the control 2679 and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 8.3. Test for less than 2 Ω in the control 2679 end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K9 Body Control Module ⇒ If the test lamp is always ON 8.1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON. 8.2. Test for less than 1 V between the control 2679 and ground. ⇒ If 1 V or greater, repair the short to voltage on the circuit. ⇒ If less than 1 V, replace the K9 Body Control Module ⇓ If the test lamp turns ON and OFF
14. Test or replace the component: A23D Front Side Door Latch-Driver Test 2
15. Ignition/Vehicle » Off
16. Disconnect the electrical connector: A23LR Rear Side Door Latch - Left
17. Connect a test lamp between the test points: Control circuit terminal 8 & ground
18. Ignition » On / Vehicle » In Service Mode
19. Operate the component: S13D Door Lock Switch - Driver Verify the test lamp state: Not used= Test lamp Off Unlock» Pressed = Test lamp flashes ON and OFF ⇒ If the test lamp is always OFF 5.1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module 5.2. Test for infinite resistance between the control 2679 and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 5.3. Test for less than 2 Ω in the control 2679 end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K9 Body Control Module ⇒ If the test lamp is always ON 5.1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON. 5.2. Test for less than 1 V between the control 2679 and ground. ⇒ If 1 V or greater, repair the short to voltage on the circuit. ⇒ If less than 1 V, replace the K9 Body Control Module ⇓ If the test lamp turns ON and OFF
20. Connect a test lamp between the test points: Control circuit terminal 9 & Ground
21. Operate the component: child lock switch» Pressed — On and Off Verify the test lamp state: Not Used = Test lamp always OFF Child lock switch» Pressed — On and Off = Test lamp flashes ON and OFF ⇒ If the test lamp is always OFF 7.1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module 7.2. Test for infinite resistance between the control 3266 and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 7.3. Test for less than 2 Ω in the control 3266 end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K9 Body Control Module ⇒ If the test lamp is always ON 7.1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON. 7.2. Test for less than 1 V between the control 3266 and ground. ⇒ If 1 V or greater, repair the short to voltage on the circuit. ⇒ If less than 1 V, replace the K9 Body Control Module ⇓ If the test lamp turns ON and OFF
22. Test or replace the component: A23LR Rear Side Door Latch - Left Component Testing
23. Ignition/Vehicle » Off
24. Disconnect the electrical connector: A23LR Rear Side Door Latch - Left
25. Connect a 25 A fused jumper wire between the test points: Control terminal 7 & B+

Caution

Complete the testing as quickly as possible in order to prevent overheating and damaging the component.

4. Momentarily connect a jumper wire between the test points: Control terminal 8 & Ground
5. Reverse the jumper wires 2 times between the terminals. Verify the component works as specified: A23LR Rear Side Door Latch - Left = Lock & Unlock ⇒ If not the specified state Replace the component: A23LR Rear Side Door Latch - Left ⇓ If the specified state
6. Connect a 25 A fused jumper wire between the test points: Control terminal 8 & B+

Caution

Complete the testing as quickly as possible in order to prevent overheating and damaging the component.

7. Momentarily connect a jumper wire between the test points: A23LR Door Latch Assembly - Left Rear :Control terminal 9 & Ground
8. Reverse the jumper wires 2 times between the terminals. Verify the component works as specified: A23LR Rear Side Door Latch - Left = Lock & Unlock ⇒ If not the specified state Replace the component: A23LR Rear Side Door Latch - Left ⇓ If the specified state
9. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Rear Side Door Latch Replacement For control module replacement, programming, and setup refer to: Control Module References