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DTC Troubleshooting

NOTE: Before this trouble shooting is performed, read the precautions for DTC troubleshooting by referring to PRECAUTIONS FOR DTC TROUBLESHOOTING .
TROUBLESHOOTING TABLE

Step Action YES NO
1  Was "Engine and Emission Control System Check" performed?  Go to Step 2. Go to ENGINE AND EMISSION CONTROL SYSTEM CHECK .
2  DTC check 
  1. Connect scan tool to DLC with ignition switch turned OFF.
  2. Check for all control modules (ECM, TCM (if equipped), BCM, ABS or ESP® control module, 4WD control module (if equipped), keyless start control module (if equipped), combination meter, steering angle sensor (if equipped)) for DTC(s) other than CAN communication DTCs.

Is there any DTC(s) other than CAN communication DTC(s) at each control module (other than DTC U0073, U0100, U0101, U0121, U0140, U1073, U1100, U1101, U1121, U1126, U1139, U1140, U1144)? 		 Go to applicable DTC diagnosis flow. Go to Step 3.
3  DTC check 
Is DTC U0121 and U0073 detected together? 		 Go to DTC U0073: CONTROL MODULE COMMUNICATION BUS OFF . Go to Step 4.
4  ECM and ABS or ESP® control module connector check 
  1. Check for proper connection at each ECM and ABS or ESP® control module connector terminals with ignition switch turned OFF.
  2. If connections are OK, recheck ECM for DTC with engine running.

Is there DTC U0121? 		 Go to Step 5. Intermittent trouble. Check for intermittent or poor connection.
5  ECM power and ground circuit check 
  1. Check ECM power and ground circuits by referring to ECM POWER AND GROUND CIRCUIT CHECK .

Are they in good condition? 		 Go to Step 6. Repair ECM power and/or ground circuits.
6  DTC check in ABS or ESP® control module assembly 
  1. Check DTC U1073 in ABS or ESP® control module assembly.

Is it indicated? 		 Go to DTC U1073: CONTROL MODULE COMMUNICATION BUS OFF or DTC U1073: CONTROL MODULE COMMUNICATION BUS OFF . Go to Step 7.
7  DTC check 
  1. Disconnect connectors from ABS or ESP® control module and ECM.
  2. Check that CAN communication circuit is as follows.
    • Circuit resistance of CAN communication circuit is less than 1 Ω between ECM connector and ABS or ESP® connector.

Is it in good condition? 		 Go to Step 9. Go to Step 8.
8  ECM circuit check 
  1. Connect connector to ABS or ESP® control module with ignition switch turned OFF.
  2. Measure resistance at following connector terminals.
    • Between "WHT/BLU" and "WHT" terminals of ABS or ESP® control module connector.
    • Between "WHT/RED" and "RED" terminals of ABS or ESP® control module connector.

Is resistance below 1 Ω? 		 CAN communication circuit wire between ABS or ESP® control module and ECM connector is open or high resistance. Substitute a known-good ABS or ESP® control module assembly and recheck.
9  DTC check in ECM 
  1. Connect connectors to ABS or ESP® control module and ECM with ignition switch turned OFF.
  2. Disconnect connector from BCM with ignition switch turned OFF.
  3. Check ECM for DTC(s).

Is there DTC U0121? 		 Go to Step 10. CAN communication circuit wire between BCM and CAN circuit junction connector is open or high resistance. If wires are OK, check BCM power and ground circuits. If circuits are OK, substitute a known-good BCM and recheck.
10  DTC check in ECM 
  1. Disconnect connectors from TCM (for A/T model) with ignition switch turned OFF.
  2. Check ECM for DTC.

Is there DTC U0121? 		 Go to Step 11. CAN communication circuit wire between TCM and CAN circuit junction connector is open or high resistance. If wires are OK, check TCM power and ground circuits. If circuits are OK, substitute a known-good TCM (for A/T model) and recheck.
11  DTC check in ECM 
  1. Disconnect connector from keyless start control module (if equipped) with ignition switch turned OFF.
  2. Check ECM for DTC.

Is there DTC U0121? 		 Go to Step 10. CAN communication circuit wire between keyless start control module and CAN circuit junction connector is open or high resistance. If wires are OK, check keyless start control module power and ground circuits. If circuits are OK, substitute a known-good keyless start control module and recheck.
12  DTC check in ECM 
  1. Disconnect connector from combination meter with ignition switch turned OFF.
  2. Check ECM for DTC.

Is there DTC U0121? 		 Go to Step 11. CAN communication circuit wire between combination meter and CAN circuit junction connector is open or high resistance. If wires are OK, check combination meter power and ground circuits. If circuits are OK, substitute a known-good combination meter and recheck.
13  DTC check in ECM 
  1. Disconnect connector from 4WD control module (if equipped) with ignition switch turned OFF.
  2. Check ECM for DTC.

Is there DTC U0121? 		 Go to Step 12. CAN communication circuit wire between 4WD control module and CAN circuit junction connector is open or high resistance. If wires are OK, check 4WD control module power and ground circuits. If circuits are OK, substitute a known-good 4WD control module and recheck.
14  DTC check 
  1. Disconnect connector from steering angle sensor (if equipped ESP®) with ignition switch turned OFF.
  2. Check ECM for DTC.

Is there DTC U0121? 		 Go to Step 15. CAN communication circuit wire between steering angle sensor and CAN circuit junction connector is open or high resistance. If wires are OK, check steering angle sensor power and ground circuits. If circuits are OK, substitute a known good steering angle sensor and recheck.
15  DTC check 
  1. Disconnect connectors from all control modules (ECM, TCM (if equipped), BCM, ABS or ESP® control module, 4WD control module (if equipped), keyless start control module (if equipped), combination meter, steering angle sensor (if equipped)) with ignition switch turned OFF.
  2. Check that CAN communication circuit is as follows.
    • ALL wire harness resistance of CAN communication circuit is less than 1 Ω between each control module.
    • Insulation resistance between CAN communication circuit wires is infinity at each control module connector.
    • Insulation resistance between each CAN communication circuit wire and vehicle body ground is infinity at each control module connector.
    • Circuit voltage of CAN communication circuit is 0 V with ignition switch turned ON.

Are they in good condition? 		 Go to Step 16. Repair or replace defective CAN communication circuit.
16  ABS warning light check 
  1. Connect connectors to all control modules communicating by CAN.
  2. Turn ignition switch ON.

Is ABS warning light illuminated? 		 Substitute a known-good ABS or ESP® control module assembly and recheck. Substitute a known-good ECM and recheck.
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