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Body Control Modules: Diagnosis GMC Yukon Denali

Body, Cab Control Systems 6 illustrations ~3926 words

BCM DIAGNOSTIC SYSTEM CHECK

  1. Connect scan tool to Data Link Connector (DLC). If scan tool does not power up, go to «SCAN TOOL DOES NOT POWER UP»(ref-8996-S28652405562000100200000) . If scan tool powers up, go to next step.
  2. Turn ignition on. Attempt to establish communication with BCM. If scan tool communicates with BCM, go to next step. If scan tool does not communicate with BCM, go to «SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE»(ref-8996-S15203242282000100200000) .
  3. Select BCM Display DTCs function on scan tool. If scan tool displays any DTCs, go to next step. If scan tool does not display any DTCs, diagnose system by symptom. See appropriate article for malfunctioning system.
  4. If scan tool displays any DTCs beginning with a "U", go to «SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE»(ref-8996-S15203242282000100200000) . If scan tool does not display any DTCs beginning with a "U", perform appropriate test. See «BODY CONTROL SYSTEM DIAGNOSTIC TROUBLE CODE INDEX»(ref-8996-S02272919312000100200000) table.
DTCDescription
B0016 (1)Right Front/Passenger Frontal Deployment Loop (Single Stage Or Stage 1) Resistance Low
B0017 (1)Right Front/Passenger Frontal Deployment Loop (Single Stage Or Stage 1) Open
B0018 (1)Right Front/Passenger Frontal Deployment Loop (Single Stage Or Stage 1) Short To Ground/Voltage Out Of Range
B0022 (1)Left Front/Driver Frontal Deployment Loop (Single Stage Or Stage 1) Resistance Low
B0024 (1)Left Front/Driver Frontal Deployment Loop (Single Stage Or Stage 1) Short To Ground/Voltage Out Of Range
B0026 (1)Left Front/Driver Frontal Deployment Loop (Single Stage Or Stage 1) Open
B0028 (1)Right Front/Passenger Side Deployment Loop Resistance Low
B0029 (1)Right Front/Passenger Side Deployment Loop Open
B0030 (1)Right Front/Passenger Side Deployment Loop Short To Ground/Voltage Out Of Range
B0035 (1)ADS Closed/Shorted To Ground
B0036 (1)ADS Open/Missing/Shorted To Battery
B0040 (1)Left Front/Driver Side Deployment Loop Resistance Low
B0041 (1)Left Front/Driver Side Deployment Loop Open
B0045 (1)Left Front Side Deploy Loop Short To Ground/Voltage Out Of Range
B0051 (1)Deployment Commanded
B0053 (1)Deployment Commanded With Loop Malfunctions Present
B0077 (1)Left Front/Driver SIS Malfunction
B0078 (1)Right Front/Passenger SIS Malfunction
B0079 (1)Incorrect Left Front/Driver SIS Installed
B0080 (1)Discard Left Front/Driver SIS
B0081 (1)Incorrect Right Front/Passenger SIS Installed
B0082 (1)Discard Right Front/Passenger SIS
B0090 (1)Active Switch: Voltage Out of Range
B0091 (1)Active Switch: Wrong State
B0159 (3)Outside Air Temperature Sensor Circuit Range/Performance
B0164 (3)Passenger Compartment Temperature Sensor No. 1 (Single Sensor or Left Side) Circuit Range/Performance
B0174 (3)Output Air Temperature Sensor No. 1 (Upper, Single or Left Side) Circuit Range/Performance
B0179 (3)Output Air Temperature Sensor No. 2 (Lower, Single or Left Side) Circuit Range/Performance
B0184 (3)Solar Load Sensor No. 1 CKT Range
B0229 (3)Air Flow Control No. 7 (Recirc) Feedback Circuit Range/Performance
B0248 (3)Mode Door Inoperative Error
B0268 (3)Air Flow Control No. 7 (Recirc) Circuit Malfunction
B0408 (3)Temperature Control No. 1 (Main/Front) Circuit Malfunction
B0414 (3)Temperature Control No. 1 (Main/Front) Feedback Circuit Range/Performance
B0429 (3)Air Mix Door No. 3 Range Error
B0434 (3)Temperature Control No. 3 Rear Feedback Circuit Range
B1000 (1) (2)ECU Malfunction
B1001 (1)Option Configuration Error
B1004 (2)Keep Alive Memory (KAM) Reset
B1009 (2)EEPROM Checksum Error
B1020 (3)Auxiliary ECU Malfunction
B1367 (4)IPC Ignition 0 Circuit Low
B1397 (5)Device Voltage Reference Output No. 1 Circuit Low
B1398 (5)Device Voltage Reference Output No. 1 Circuit High
B1477 (6)Retained Accessory Power Circuit Low
B1478 (6)Retained Accessory Power Circuit High
B1480 (5)Battery Rundown Protection Circuit Malfunction
B2462 (2)GPS Signal Error
B2476 (2)Cellular Phone Select Service Switch Malfunction
B2527 (7)Front Fog Light Circuit Low
B2577 (7)Headlight Control Circuit Low
B2585 (8)Parking Light Control Circuit Malfunction
B2613 (9)Passenger Compartment Dimming No. 1 Circuit High
B2617 (9)Passenger Compartment Dimming No. 2 Circuit Low
B2618 (9)Passenger Compartment Dimming No. 2 Circuit High
B2642 (8)Delayed Exterior Lighting Control Circuit Low
B2643 (8)Delayed Exterior Lighting Control Circuit High
B2647 (7)Ambient Light Sensor Circuit Low
B2648 (7)Ambient Light Sensor Circuit High
B2722 (10)Transmission Preference Switch Circuit Low
B2752 (11)Horn Relay Coil Circuit Low
B2947 (12)Security System Sensor Power Circuit Low
B2948 (12)Security System Sensor Power Circuit High
B2957 (12)Security System Sensor Data Circuit Low
B2958 (12)Security System Sensor Data Circuit High
B2960 (12)Security System Sensor Data Incorrect But Valid
B2961 (12)Key In Ignition Circuit Malfunction
B2973 (12)Left Front Door Key Switch Circuit Low
B3031 (12)Security System Controller in Learn Mode
B3033 (12)Security System Indicates Tamper
B3102 (13)Keyless Entry Data Link Circuit Low
B3137 (14)All Door Lock Circuit Low
B3138 (14)All Door Lock Circuit High
B3147 (14)Right Front Unlock Switch Circuit Low
B3148 (14)Right Front Unlock Switch Circuit High
B3531 (3)Air Flow Control No. 10 Rear Circuit Malfunction
B3579 (3)Output Air Temperature Sensor No. 6 Circuit Range/Performance
B3584 (3)Output Air Temperature Sensor No. 7 Circuit Range/Performance
B3761 (3)Air Flow Control No. 3 (Blend Defog/Floor) Feedback Circuit Range/Performance
B3764 (3)Airflow Control No. 4 Mode Feedback Circuit Malfunction
U1000 & U1255 (5)Class 2 Communication Malfunction
U1001-U1254 (5)Loss of XXX Communications
U1300 (5)Class 2 Data Link Low
U1301 (5)Class 2 Data Link High
U1500 (3)Communication (Front-To-Rear) State Of Health
U1500 (2)Inter-Device Dedicated Bus Malfunction
(1) For information on air bag DIAGNOSIS & TESTING or DISPOSAL PROCEDURES, see AIR BAG SERVICE & REPAIR MANUAL, DOMESTIC & IMPORTED MODELS. (2) Repair OnStar® system as necessary. (3) Perform appropriate diagnostic procedure. See appropriate AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. (4) Perform appropriate diagnostic procedure. See appropriate ANALOG INSTRUMENT PANELS article. (5) Perform appropriate test under DIAGNOSTIC TESTS. (6) Repair appropriate circuit as necessary. See WIRING DIAGRAMS. (7) Repair appropriate circuit as necessary. See HEADLIGHT SYSTEMS & DAYTIME RUNNING LIGHTS article. (8) Repair appropriate circuit as necessary. See EXTERIOR LIGHTS article. (9) Repair appropriate circuit as necessary. See ILLUMINATION/INTERIOR LIGHTS article. (10) Perform appropriate diagnostic procedure. See appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS. (11) Perform appropriate diagnostic procedure. See appropriate STEERING COLUMN SWITCHES article. (12) Perform appropriate diagnostic procedure. See appropriate ANTI-THEFT SYSTEMS article. (13) Perform appropriate diagnostic procedure. See appropriate REMOTE KEYLESS ENTRY SYSTEMS article. (14) Perform appropriate diagnostic procedure. See appropriate POWER DOOR LOCKS article.
(1)For information on air bag DIAGNOSIS & TESTING or DISPOSAL PROCEDURES, see AIR BAG SERVICE & REPAIR MANUAL, DOMESTIC & IMPORTED MODELS.
(2)Repair OnStar® system as necessary.
(3)Perform appropriate diagnostic procedure. See appropriate AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
(4)Perform appropriate diagnostic procedure. See appropriate ANALOG INSTRUMENT PANELS article.
(5)Perform appropriate test under DIAGNOSTIC TESTS.
(6)Repair appropriate circuit as necessary. See WIRING DIAGRAMS .
(7)Repair appropriate circuit as necessary. See HEADLIGHT SYSTEMS & DAYTIME RUNNING LIGHTS article.
(8)Repair appropriate circuit as necessary. See EXTERIOR LIGHTS article.
(9)Repair appropriate circuit as necessary. See ILLUMINATION/INTERIOR LIGHTS article.
(10)Perform appropriate diagnostic procedure. See appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS.
(11)Perform appropriate diagnostic procedure. See appropriate STEERING COLUMN SWITCHES article.
(12)Perform appropriate diagnostic procedure. See appropriate ANTI-THEFT SYSTEMS article.
(13)Perform appropriate diagnostic procedure. See appropriate REMOTE KEYLESS ENTRY SYSTEMS article.
(14)Perform appropriate diagnostic procedure. See appropriate POWER DOOR LOCKS article.

BODY CONTROL SYSTEM DIAGNOSTIC TROUBLE CODE INDEX

Testing

  1. Connect scan tool to Data Link Connector (DLC). If scan tool does not power up, go to «SCAN TOOL DOES NOT POWER UP»(ref-8996-S28652405562000100200000). If scan tool powers up, go to next step.
  2. Turn ignition on. Attempt to communicate with each module on class 2 serial data line. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. If scan tool communicates with one or modules, go to next step. If scan tool does not communicate with any module, go to step 5.
  3. Select Display DTCs function for each module. Record all DTCs, DTC status and which module set the DTC(s). If any DTCs between DTC U1000 and U1255 are set, go to next step. If no DTCs between DTC U1000 and U1255 are set, go to «DIAGNOSTIC AIDS»(ref-8996-S13496802772000100200000).
  4. If only DTC U1000 or U1255 is set, go to «DTC U1000 OR U1255: CLASS 2 COMMUNICATION MALFUNCTION»(ref-8996-S06169872362000100200000) under DIAGNOSTIC TESTS. If other DTC(s) between DTC U1000 and U1255 are set, go to «DTC U1001-U1254: LOSS OF XXX COMMUNICATION»(ref-8996-S40792868442000100200000) under DIAGNOSTIC TESTS.
  5. Turn ignition off. Disconnect scan tool from DLC. Inspect DLC terminals No. 2 and 5 for poor connections. (Scheme 1) Repair connector as necessary. Perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If connector is okay, go to next step.
  6. Check for open in ground circuit between DLC terminal No. 5 (Black/White wire) and ground. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. Repair circuit as necessary. Perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If circuit is okay, go to next step.
  7. Disconnect splice pack SP205. Inspect splice pack SP205 for poor connections. Repair splice pack as necessary and perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If splice pack is okay, go to next step.
  8. Check for open or short in class 2 serial data line (Purple wire) between DLC terminal No. 2 and splice pack SP205 terminal "A". (Scheme 2) See DATA LINK CONNECTORS article in WIRING DIAGRAMS. Repair circuit as necessary and perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If circuit is okay, go to next step.
  9. Using Connector Adapter Kit (J35616-A), connect a jumper wire between splice pack SP205 terminals "A" (Purple wire) and "M" (Light Green wire). Turn ignition on. Attempt to communicate with BCM. If scan tool communicates with BCM, go to step 11. If scan tool does not communicate with BCM, go to next step.
  10. Turn ignition off. Disconnect Brown BCM harness connector. Check for short to ground or voltage in class 2 serial data line (Light Green wire) between splice pack SP205 terminal "M" and BCM harness connector C1 terminal A12. (Scheme 3) Repair circuit as necessary and go to step 28. If circuit is okay, go to step 26.
  11. Turn ignition off. Connect another jumper wire between jumper wire connected to splice pack SP205 terminal "A" and splice pack SP205 terminal "B" (Dark Green wire). Turn ignition on. Attempt to communicate with Powertrain Control Module (PCM) or Vehicle Control Module (VCM). If scan tool communicates with PCM or VCM, go to step 13. If scan tool does not communicate with PCM or VCM, go to next step.
  12. Turn ignition off. Disconnect PCM/VCM harness connectors. Check for short to ground or voltage in class 2 serial data line (Dark Green wire) between splice pack SP205 terminal "B" and VCM harness connector C4 terminal No. 11 (4.3L engine) or PCM harness connector C1 terminal No. 58 (all other gas engines). Repair circuit as necessary and go to step 28. If circuit is okay, go to step 26.
  13. Turn ignition off. Move jumper wire from splice pack SP205 terminal "B" to terminal "C" (Dark Green/White wire). Turn ignition on. Attempt to communicate with Automatic Transfer Case (ATC) module. If scan tool communicates with ATC module, go to step 15. If scan tool does not communicate with ATC module, go to next step.
  14. Turn ignition off. Disconnect ATC module harness connectors. Check for short to ground or voltage in class 2 serial data line (Dark Green/White wire) between splice pack SP205 terminal "C" and ATC module harness connector C1 terminal E9. Repair circuit as necessary and go to step 28. If circuit is okay, go to step 26.
  15. Turn ignition off. Move jumper wire from splice pack SP205 terminal "C" to terminal "E" (Light Blue wire). Turn ignition on. Attempt to communicate with Electronic Brake Control Module (EBCM). If scan tool communicates with EBCM, go to step 17. If scan tool does not communicate with EBCM, go to next step.
  16. Turn ignition off. Disconnect EBCM harness connectors. Check for short to ground or voltage in class 2 serial data line (Light Blue wire) between splice pack SP205 terminal "E" and EBCM harness connector C2 terminal B6. Repair circuit as necessary and go to step 28. If circuit is okay, go to step 26.
  17. Turn ignition off. Move jumper wire from splice pack SP205 terminal "E" to terminal "F" (Dark Blue wire). Turn ignition on. Attempt to communicate with inflatable restraint Sensing and Diagnostic Module (SDM). If scan tool communicates with SDM, go to step 19. If scan tool does not communicate with SDM, go to next step.
  18. Turn ignition off. Disconnect SDM harness connectors. Check for short to ground or voltage in class 2 serial data line (Dark Blue wire) between splice pack SP205 terminal "F" and SDM harness connector C1 terminal A4. Repair circuit as necessary and go to step 28. If circuit is okay, go to step 26.
  19. Turn ignition off. Move jumper wire from splice pack SP205 terminal "F" to terminal "G" (Gray wire). Turn ignition on. Attempt to communicate with Instrument Panel Cluster (IPC) If scan tool communicates with IPC, go to step 21. If scan tool does not communicate with IPC, go to next step.
  20. Turn ignition off. Disconnect IPC harness connector. Check for short to ground or voltage in class 2 serial data line (Gray wire) between splice pack SP205 terminal "G" and IPC harness connector terminal A5. Repair circuit as necessary and go to step 28. If circuit is okay, go to step 26.
  21. Turn ignition off. Move jumper wire from splice pack SP205 terminal "G" to terminal "H" (Dark Blue/White wire). Turn ignition on. Attempt to communicate with Suspension Control Module (SCM). If scan tool communicates with SCM, go to step 23. If scan tool does not communicate with SCM, go to next step.
  22. Turn ignition off. Disconnect SCM harness connectors. Check for short to ground or voltage in class 2 serial data line (Dark Blue/White wire) between splice pack SP205 terminal "H" and SCM harness connector C2 terminal B8. Repair circuit as necessary and go to step 28. If circuit is okay, go to step 26.
  23. Turn ignition off. Move jumper wire from splice pack SP205 terminal "H" to terminal "L" (White wire). Turn ignition on. Attempt to communicate with Heating, Ventilation & Air Conditioning (HVAC) control module. If scan tool communicates with HVAC control module, go to step 25. If scan tool does not communicate with HVAC control module, go to next step.
  24. Turn ignition off. Disconnect HVAC control module harness connector. Check for short to ground or voltage in class 2 serial data line (White wire) between splice pack SP205 terminal "L" and HVAC control module harness connector terminal C11. Repair circuit as necessary and go to step 28. If circuit is okay, go to step 26.
  25. Turn ignition off. Check for short to ground or voltage in class 2 serial data line (Orange wire) between splice pack SP205 terminal "D" and cellular phone ready wiring at body wiring harness junction block harness connector C1 terminal A2. Repair circuit as necessary and go to step 28. If circuit is okay, go to «DIAGNOSTIC AIDS»(ref-8996-S13496802772000100200000).
  26. Inspect harness connector of non-communicating module for poor connections. Repair connector as necessary and go to step 28. If connector is okay, go to next step.
  27. Replace non-communicating module. See appropriate procedure under REMOVAL & INSTALLATION. Go to next step.
  28. Reconnect all harness connectors. Connect scan tool to DLC. Turn ignition on. Wait 10 seconds. Scan tool may require a power up reset before communication will occur. Turn ignition off and disconnect scan tool. Reconnect scan tool and turn ignition on. Display DTCs for each module. Record DTC(s) and DTC status. If any current DTCs that begin with a "U" are present, go to step 30. If no current DTCs that begin with a "U" are present, go to next step.
  29. If any DTCs that do not begin with a "U" are present, go to next step. If no DTCs that do not begin with a "U" are present, go to step 32.
  30. Perform appropriate diagnostic procedure for DTC(s) present. See appropriate article for malfunctioning system. After repairs, go to next step.
  31. If all DTCs have been diagnosed, go to next step. If any DTCs have not been diagnosed, go to step 30.
  32. Using scan tool, clear DTCs. System is okay.

Scheme 1

Scheme 1: Data Link Connector Terminals
Scheme 1: Data Link Connector Terminals

Scheme 2

Scheme 2: Splice Pack SP205 Connector Terminals
Scheme 2: Splice Pack SP205 Connector Terminals

Scheme 3

Scheme 3: BCM Connector Terminals With Pinouts
Scheme 3: BCM Connector Terminals With Pinouts
Connector Part Information* 12160778 * 24 Way F Micro-Pack 100 Series (BRN)
PinWire ColorCircuit No.Function
A1BLK1850Ground
A2ORN1140Fused Battery Positive Voltage
A3WHT194Power Door Lock Relay Feed - Unlock Coil
A4LT BLU195Power Door Lock Relay Feed - Lock Coil
A5BRN1295Electronic Variable Orifice (EVO) Solenoid Output
A6WHT1294Electronic Variable Orifice (EVO) Solenoid Feed
A7BLK755Delayed Accessory Bus Relay Output Coil
A8DK BLU1393Interior Lamp Relay Control - Coil
A9BLK28Horn Relay Output - Coil
A10Not Used
A11LT GRN/BLK592Daytime Running Lamp Relay Output - Coil
A12LT GRN1037Serial Data Signal (Class 2)
B1BLK1850Ground
B2PNK39Fused Ignition Positive Voltage
B3RED/WHT812Reference Voltage Feed - 12 Volt
B4ORN461Serial Data Signal
B5GRY705Reference Voltage Feed - 5 Volt
B6LT BLU14LH Turn Signal Lamp Input
B7DK BLU15RH Turn Signal Lamp Input
B8Not Used
B9BRN41Fused Ignition 3 Output
B10LT BLU1134Park Brake Switch Signal
B11BLK/WHT238Seat Belt Switch Signal
B12LT BLU553Tow/Haul Switch Input

BCM Connector C1 Terminal Pinouts

Scheme 4

Scheme 4
Scheme 4
Connector Part Information* 12110206 * 24 Way F Micro-Pack 100 Series (LT BLU)
PinWire ColorCircuit No.Function
A1YEL710Serial Data Signal (Class 2)
A2ORN/BLK1057Sensor Return (Passlock)
A3GRY/BLK690Courtesy Lamp Relay Output (Coil)
A4LT GRN1391Power Door Lock Relay Control - LF
A5WHT1080Park Lamp Relay Output (Coil)
A6Not Used
A7DK GRN/WHT1317Fog Lamp Relay Output (Coil)
A8DK GRN1655Perimeter Lighting Relay Output
A9 -A10Not Used
A11WHT352Headlamp Relay Feed (Coil)
A12PPL/WHT1382LED Dimming Signal
B1DK GRN/WHT817Vehicle Speed Signal
B2LT BLU1059Steering Wheel Position Sensor Signal
B3YEL1836Passlock Sensor Signal
B4Not Used
B5PPL524Headlamp Dimmer Switch Output (High Beam)
B6BRN2409Fused Interior Park Lamps Feed
B7-B8Not Used
B9LT GRN80Key Reminder Switch Signal
B10PNK/BLK1303Liftgate Ajar Switch Signal
B11DK BLU/WHT727Door Latch Switch Signal
B12ORN1732Inadvertant Power Relay Status

BCM Connector C2 Terminal Pinouts

Scheme 5

Scheme 5
Scheme 5
Connector Part Information* 12191375 * 16 Way F Micro-Pack 100 Series (PPL)
PinWire ColorCircuit No.Function
A1DK BLU/WHT149Cargo Lamp Switch Input
A2DK BLU/WHT1495Courtesy Lamp Switch Output
A3BRN1356Flash to Pass Switch Signal
A4GRY705Reference Voltage Feed - 5 Volt
A5GRY8Instrument Panel Lamp Feed
A6WHT278Photocell Signal
A7-B1Not Used
B2ORN54Door Jamb Switch Signal - Passenger
B2LT GRN/BLK394Door Handle Switch Signal - (Uplevel)
B3LT GRN262Door Key Lock Cylinder Switch Signal - Driver (Uplevel)
B4TAN126Door Latch Switch Signal - LH Front
B5ORN192Fog Lamp Switch Input
B6PPL328Interior Lamp Defeat Switch Output
B7-B8Not Used

BCM Connector C3 Terminal Pinouts

Diagnostic Aids

When class 2 serial data line is shorted to ground, DTC U1300 will be set. When class 2 serial data line is shorted to voltage DTC U1301 will be set.

SCAN TOOL DOES NOT POWER UP

  1. Check for battery voltage at Data Link Connector (DLC) terminal No. 16 (Orange wire). (Scheme 1) If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short to ground in Orange wire between DLC and CIGAR fuse (15-amp) located in engine wiring harness junction block. Perform appropriate diagnostic system check. See appropriate article for malfunctioning system.
  2. Check for open in Black wire between DLC terminal No. 4 and ground. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. Repair circuit as necessary and perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If ground circuit is okay, go to next step.
  3. Check for poor connections between scan tool and DLC terminals No. 4 and 16. Repair as necessary and perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If no problems are found, go to next step.
  4. Scan tool may be malfunctioning. Check scan tool manual for diagnostic procedures. After repairs, perform appropriate diagnostic system check. See appropriate article for malfunctioning system.
  1. If BCM diagnostic system check has been performed, go to next step. If BCM diagnostic system check has not been performed, perform BCM diagnostic system check. See «BCM DIAGNOSTIC SYSTEM CHECK»(ref-8996-S23737668762000100200000) under SELF-DIAGNOSTIC SYSTEM.
  2. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, observe Ambient Light Sensor parameter in BCM data list. If scan tool displays 0.2-4.7 volts, go to «DIAGNOSTIC AIDS»(ref-8996-S21462951572000100200000). If scan tool does not display 0.2-4.7 volts, go to next step.
  3. Turn ignition off. Disconnect ambient light sensor harness connector. Turn ignition on. If scan tool displays less than.2 volt, go to next step. If scan tool displays.2 volt or more, go to step 9.
  4. Turn ignition off. Connect a 3-amp fused jumper wire between ambient light sensor harness connector terminals. Turn ignition on. If scan tool displays more than 4.7 volts, go to next step. If scan tool displays 4.7 volts or less, go to step 7.
  5. Remove jumper wire. Measure voltage between ambient light sensor harness connector terminals. If voltage is less than 5.25 volts, go to step 10. If voltage is 5.25 volts or more, go to next step.
  6. Check for short to voltage in Gray wire between ambient light sensor harness connector terminal "A" and BCM harness connector C3 terminal A4. (Scheme 6) Repair circuit as necessary and go to step 14. If circuit is okay, go to step 11.
  7. Check for short to ground in Gray wire between ambient light sensor harness connector terminal "A" and BCM harness connector C3 terminal A4. Repair circuit as necessary and go to step 14. If circuit is okay, go to next step.
  8. Check for open, high resistance or short to ground in White wire between ambient light sensor harness connector terminal "B" and BCM harness connector C3 terminal A6. Repair circuit as necessary and go to step 14. If circuit is okay, go to step 11.
  9. Check for short to voltage in White wire between ambient light sensor harness connector terminal "B" and BCM harness connector C3 terminal A6. Repair circuit as necessary and go to step 14. If circuit is okay, go to step 11.
  10. Inspect ambient light sensor harness connector for poor connections. Repair connector as necessary and go to step 14. If connector is okay, go to step 12.
  11. Inspect BCM harness connector for poor connections. Repair connector as necessary and go to step 14. If connector is okay, go to step 13.
  12. Replace ambient light sensor. Go to step 14.
  13. Replace BCM. See «BODY CONTROL MODULE (BCM)»(ref-8996-S37032662682000100200000) under REMOVAL & INSTALLATION. Go to next step.
  14. Using scan tool, clear DTCs. Retest system. If DTC resets, go to step 2. If DTC does not reset, system is okay.

Scheme 6

Scheme 6
Scheme 6

A short to ground or voltage in Gray wire will only cause this DTC to be set. Check for loose or poor connections at all related components.

  1. If BCM diagnostic system check has been performed, go to next step. If BCM diagnostic system check has not been performed, perform BCM diagnostic system check. See «BCM DIAGNOSTIC SYSTEM CHECK»(ref-8996-S23737668762000100200000) under SELF-DIAGNOSTIC SYSTEM.
  2. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, command inadvertent power relay on and off. If inadvertent power relay turns on and off with each command, go to «DIAGNOSTIC AIDS»(ref-8996-S31718770002000100200000). If inadvertent power relay does not turn on and off with each command, go to next step.
  3. Turn ignition off. Remove inadvertent power relay. Turn ignition on. Using a test light connected to ground, probe inadvertent power relay coil power supply cavity (relay terminal No. 1) in body wiring harness junction block. If test light illuminates, go to next step. If test light does not illuminate, go to step 10.
  4. Move test light ground to inadvertent power relay control circuit cavity (relay terminal No. 2) in body wiring harness junction block. Using scan tool, command inadvertent power relay on and off. If test light turns on and off with each command, go to step 8. If test light does not turn on and off with each command, go to next step.
  5. If test light remains on with each command, go to step 7. If test light does not remain on with each command, go to next step.
  6. Check for open or short to voltage in inadvertent power relay control circuit (Dark Blue wire) between BCM harness connector C1 terminal A8 and body wiring harness junction block harness connector C2 terminal A2. (Scheme 3) Repair circuit as necessary and go to step 13. If circuit is okay, go to step 9.
  7. Check for short to ground in inadvertent power relay control circuit (Dark Blue wire) between BCM harness connector C1 terminal A8 and body wiring harness junction block harness connector C2 terminal A2. Repair circuit as necessary and go to step 13. If circuit is okay, go to step 9.
  8. Check for poor connections between inadvertent power relay and body wiring harness junction block. Repair as necessary and go to step 13. If connections are okay, go to step 11.
  9. Inspect BCM harness connector for poor connections. Repair connector as necessary and go to step 13. If connector is okay, go to step 12.
  10. Repair inadvertent power relay coil power supply circuit between inadvertent power relay and battery. See POWER DISTRIBUTION article in WIRING DIAGRAMS. Go to step 13.
  11. Replace inadvertent power relay. Go to step 13.
  12. Replace BCM. See «BODY CONTROL MODULE (BCM)»(ref-8996-S37032662682000100200000) under REMOVAL & INSTALLATION. Go to next step.
  13. Using scan tool, clear DTCs. Retest system. If DTC resets, go to step 2. If DTC does not reset, system is okay.

Check for loose or poor connections at all related components. Check CTSY fuse (15-amp) located in engine wiring harness junction block. Check for open between CTSY fuse and body wiring harness junction block.

  1. If any history DTCs between DTC U1001 and U1199 are present, go to «DTC U1001-U1254: LOSS OF XXX COMMUNICATION»(ref-8996-S40792868442000100200000) . If no history DTCs between DTC U1001 and U1199 are present, go to next step.
  2. Turn ignition on. Using scan tool, attempt to communicate with each module on class 2 serial data line. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. If scan tool does not communicate with one or more modules, go to next step. If scan tool communicates with all modules, go to step 13 .
  3. Check power circuits for non-communicating module for open or short to ground conditions. See POWER DISTRIBUTION article in WIRING DIAGRAMS. If faulty circuit is found, repair as necessary and go to step 9 . If power circuits are okay, go to next step.
  4. Turn ignition off. Check ground circuit for non-communicating module for open condition. See GROUND DISTRIBUTION article in WIRING DIAGRAMS. If faulty circuit is found, repair as necessary and go to step 9 . If circuit is okay, go to next step.
  5. Disconnect splice pack SP205. Inspect splice pack SP205 for poor connections. Repair as necessary and go to step 9 . If splice pack is okay, go to next step.
  6. Check for open in class 2 serial data line for non-communicating module. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. Repair circuit as necessary and go to step 9 . If circuit is okay, go to next step.
  7. Check for poor connections at power and ground circuits at harness connector for non-communicating module. Repair connector as necessary and go to step 9 . If connector is okay, go to next step.
  8. Replace non-communicating module. See appropriate procedure under REMOVAL & INSTALLATION. Go to step 11 .
  9. Connect scan tool to DLC. Turn ignition on. Select display DTCs function for non-communicating module. If scan tool displays any DTCs that do not begin with a "U", perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If scan tool does not display any DTCs that do not begin with a "U", go to next step.
  10. Using scan tool, clear DTCs. Go to next step.
  11. Select display DTCs function for module that had DTC U1000 or U1255 set as current. If scan tool displays any DTCs that do not begin with a "U", perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If scan tool does not display any DTCs that do not begin with a "U", go to next step.
  12. Using scan tool, clear DTCs. System is okay.
  13. If any other DTCs are present, perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If no other DTCs are present, go to next step.
  14. Connect scan tool to DLC. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off and wait at least 5 seconds. Turn ignition on. Select display DTCs function. If DTC U1000 or U1255 is set as current, go to next step. If DTC U1000 or U1255 is not set as current, go to «DIAGNOSTIC AIDS»(ref-8996-S06505879762000100200000) .
  15. Replace module that had DTC U1000 or U1255 set as current. See appropriate procedure under REMOVAL & INSTALLATION. System is okay.

When a malfunction (such as an open fuse to a module) occurs while modules are communicating, a loss of communication DTC is set as current. When modules stop communicating (ignition is turned off), the current loss of communication DTC is cleared but the history DTC remains. When the modules begin to communicate again, the module with the blown fuse will not be learned by the other modules, so DTC U1000 or U1255 is set as current by the other modules. If the malfunction occurs while the modules are not communicating, only DTC U1000 or U1255 is set.

  1. Check for open or short to ground in power circuit(s) for non-communicating module. See POWER DISTRIBUTION article in WIRING DIAGRAMS. Repair circuit(s) as necessary and go to step 9 . If circuit(s) are okay, go to next step.
  2. Check for open in ground circuit(s) for non-communicating module. See GROUND DISTRIBUTION article in WIRING DIAGRAMS. Repair circuit(s) as necessary and go to step 9 . If circuit(s) are okay, go to next step.
  3. Disconnect splice pack SP205. Check for poor connections at splice pack SP205. Repair as necessary and go to step 7 . If splice pack is okay, go to next step.
  4. Check for open in class 2 serial data line between Data Link Connector (DLC) and splice pack SP205 for non-communicating module. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. Repair circuit as necessary and go to step 7 . If circuit is okay, go to next step.
  5. Check power, ground and class 2 serial data terminals at non-communicating module connector for poor connections or terminal tension. Repair connector as necessary and go to step 7 . If connector is okay, go to next step.
  6. Replace non-communicating module. See appropriate procedure under REMOVAL & INSTALLATION. Go to step 9 .
  7. Connect scan tool to DLC. Turn ignition on. Select display DTCs function for non-communicating module. If scan tool displays any DTCs that do not begin with a "U", perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If scan tool does not display any DTCs that do not begin with a "U", go to next step.
  8. Using scan tool, clear DTCs. Go to next step.
  9. Select display DTCs function for module that had a loss of communication DTC set. If scan tool displays any DTCs that do not begin with a "U", perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If scan tool does not display any DTCs that do not begin with a "U", go to next step.
  10. Using scan tool, clear DTCs. Continue diagnosing and clearing DTCs until all modules have been diagnosed and all DTCs have been cleared. System is okay.

DTC U1300 cannot be retrieved as current. Diagnosis for current DTC U1300 is accomplished using SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SELF-DIAGNOSTIC SYSTEM. An intermittent condition can be caused by a short to ground on the class 2 serial data line.

DTC U1301 cannot be retrieved as current. Diagnosis for current DTC U1300 is accomplished using SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SELF-DIAGNOSTIC SYSTEM. An intermittent condition can be caused by a short to voltage on the class 2 serial data line.

More articles — Body Control Modules