Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Loss Of Engine RPM Message
Monitored & Set Condition
- When Monitored: With the engine running.
- Set Condition: When the Memory Heated Seat Mirror Module does not receive the engine RPM Bus message.
Possible Causes:
- Stored Code/Communication Problems
- Memory Heated Seat Mirror Module
- Intermittent Problem
Testing
- Turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, clear LOSS OF ENGINE RPM DTC from memory heated seat/mirror module. Turn ignition off, then start engine. Wait one minute. Using scan tool, retrieve DTCs. If LOSS OF ENGINE RPM DTC resets, go to next step. If LOSS OF ENGINE RPM DTC does not reset, test is complete. Perform MEMORY HEATED SYSTEMS VERIFICATION TESTΒ under VERIFICATION TESTS.
- Check related wiring and connectors for poor connections or damage to wiring harness. See WIRING DIAGRAMSΒ . Repair any problems found as necessary. If no problems are found, replace MHSMM. See MEMORY HEATED SEAT/MIRROR MODULEΒ under REMOVAL & INSTALLATION.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
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