Automatic Transmission
DTC U0155: Lost Communication with Gauge Control ModuleNOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review General Troubleshooting Information.
1. Clear the DTC with the HDS.
2. Start the engine, and let it idle for 2 minutes.
3. Check whether DTC U0155 is indicated in the DTCs/Freeze Data in PGM-FI Mode Menu with the HDS.
Is DTC U0155 indicated in the PGM-FI system?
Yes - Troubleshoot for DTC U0155 in the PGM-FI System.
No - Go to step 4.
4. Check whether the DTC U0155 is indicated in the DTCs/Freeze Data in A/T Mode Menu with the HDS.
Is DTC U0155 indicated?
Yes - Go to step 5.
No - Intermittent failure, the system is OK at this time.
5. Update the A/T software in the PCM if it does not have the latest software, or substitute a known-good PCM.
6. Start the engine, and let it idle for 2 minutes.
7. Check for DTC(s) in the DTCs/Freeze Data in A/T Mode Menu with the HDS.
Is DTC U0155 indicated?
Yes - If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, reinstall the original PCM, then go to step 1.
No - Go to step 8.
8. Monitor the OBD STATUS for U0155 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.
Does the HDS indicate PASSED?
Yes - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other DTCs were indicated on step 7, go to the indicated DTC's troubleshooting.
No - Check for poor connections and loose terminals at the gauge control module and the PCM. If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, reinstall the original PCM, then go to step 1. If the HDS indicates NOT COMPLETED, keep idling until a result comes on.