P1679
DTC P1679: RSCD Signal Circuit MalfunctionNOTE: Information marked with an asterisk (*) applies to the CVT model.
1. Reset the ECM with the HDS.
2. Turn the ignition switch ON* (II).
3. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1679 indicated?
YES - Go to step 4.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the motor control module, TCM*, and the ECM.
4. Turn the ignition switch OFF.
5. Wait for 1 minute. If the radiator fan is running, wait for 1 minute after the radiator fan stops.
6. Disconnect motor control module connector A (31P).
7. Disconnect ECM connector E (31P).
8. Check for continuity between ECM connector terminal E17 and body ground.
Is there continuity?
YES -
- Go to step 9.*
- Repair short in the wire between the ECM (E17) and the motor control module.
N0 -
- Go to step 13.
- Go to step 17.*
9. Disconnect TCM connector C (17P).
10. Check for continuity between ECM connector terminal E17 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM (E17) and the TCM (C13).
NO - Go to step 11.
11. Connect TCM connector terminals C13 and C15 with a jumper wire.
12. Check for continuity between ECM connector terminal E17 and body ground.
Is there continuity?
YES - Repair short in the wire between the TCM (C15) and the motor control module.
NO - Update the TCM if it does not have the latest software, or substitute a known-good TCM, then recheck. If the symptom/indication goes away with a known-good TCM, replace the original TCM.
13. Connect motor control module connector terminal A20 to body ground with a jumper wire.
14. Check for continuity between ECM connector terminal E17 and body ground.
Is there continuity?
YES - Go to step 15.
NO - Repair open in the wire between the ECM (E17) and the motor control module.
15. Substitute a known-good motor control module and recheck.
16. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1679 indicated?
YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
NO - Update the motor control module if it does not have the latest software, then recheck. If the symptom/indication goes away, replace the motor control module.
17. Disconnect TCM connector C (17P).
18. Connect TCM connector terminals C13 and C15 with a jumper wire.
19. Connect motor control module connector terminal A20 to body ground with a jumper wire.
20. Check for continuity between ECM connector terminal E17 and body ground.
Is there continuity?
YES - Go to step 21.
NO - Repair open in the wire between the ECM (E17) and the motor control module.
21. Remove the jumper wire from TCM connector C (17P).
22. Reconnect the TCM connector C (17P).
23. Remove the jumper wire from motor control module connector A (31P).
24. Check for continuity between TCM connector terminals C13 and C15.
Is there continuity?
YES - Go to step 25.
NO - Update the TCM if it does not have the latest software, or substitute a known-good TCM, then recheck. If the symptom/indication goes away with a known-good TCM, replace the original TCM.
25. Substitute a known-good motor control module and recheck.
26. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1679 indicated?
YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
NO - Replace the original motor control module.