DTC Troubleshooting: U0073 (126-1), U0122 (184-1)

DTC U0073:  F-CAN Malfunction (Bus-Off)
  
  

1.Turn the ignition switch ON (II).

2.Clear the DTC with the HDS.

3.Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS.

Is DTC U0073 and/or U0122 indicated?


YES - Go to 4.


NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the VSA control unit and the ECM.n


4.Turn the ignition switch OFF, and wait 30 seconds.

5.Disconnect the VSA control unit 47P connector.

6.Disconnect ECM connector No. 2 (58P).

7.Check for continuity between ECM connector No. 2 terminal No. 47 and body ground, and between terminal No. 48* and body ground individually.

 

Is there continuity?


YES - Repair short in the wire between the VSA control unit and ECM connector No. 2 terminal No. 47 (No. 48)*, then go to 18.


NO - Go to 8.

*: CANL line

8.Check for continuity between ECM connector No. 2 terminals No. 47 and No. 48*.

 

Is there continuity?


YES - Repair short in the wire between ECM connector No. 2 terminals No. 47 and No. 48*, then go to 18.


NO - Go to 9.

*: CANL line


9.Connect VSA control unit 47P connector terminals No. 2* and No. 6 with a jumper wire.

 

10.Check for continuity between ECM connector No. 2 terminals No. 47 and No. 48*.

 

Is there continuity?


YES - Go to 11.


NO - Repair open in the wire between the VSA control unit and ECM connector No. 2 terminal No. 47 (No. 48)*, then go to 18.

*: CANL line

11.Check for continuity between VSA control unit 47P connector terminals No. 1, No. 32 and body ground individually.

 

Is there continuity?


YES - Go to 12.


NO - Repair open in the wire between the VSA control unit and G202, then go to 18.

12.Remove the jumper wire from the VSA control unit 47P connector.

13.Turn the ignition switch ON (II).

14.Measure voltage between VSA control unit 47P connector terminal No. 13 and body ground.

 

Is there battery voltage?


YES - Go to 15.


NO - Check the No. 4 ACG (10 A) fuse in the under-dash fuse/relay box. If the fuse is OK, repair open in the wire between the No. 4 ACG (10 A) fuse and the VSA control unit, then go to 18.

15.Turn the ignition switch OFF.

16.Reconnect the VSA control unit 47P connector.

17.Measure resistance between ECM connector No. 2 terminals No. 47 and No. 48*.

 

Is there about 108-132 W at room temperature?


YES - Go to 23.


NO - Substitute a known-good VSA control unit, then go to step 18 and recheck. If any DTC does not indicated, replace the original VSA control unit, then go to 18.


18.Turn the ignition switch OFF.

19.Reconnect all connectors.

20.Turn the ignition switch ON (II).

21.Reset the ECM with the HDS.

22.Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - If DTC U0073 and/or U0122 is indicated, check for poor connections or loose terminals at the VSA control unit and the ECM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


NO - Troubleshooting is complete.n

23.Update the ECM if it does not have the latest software, or substitute a known-good ECM.

24.Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - If DTC U0073 and/or U0122 is indicated, check for poor connections or loose terminals at the VSA control unit and the ECM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


NO - If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM.n