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Q: Check Engine Diagnosis - Transmission controller Communication error codes

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Check engine light came on. Transmisson would not shift from low gear. Speedometer was not registering. Stopped and restarted car. Car operated normally. Check engine light went off. Car has been operating normally. Took car to Autozone. Following was reported: P0700(indicates transmission control system). Error Codes Read P0700 (Read Fault memory of control unit ETC; U0101 (Lost communication with TCM); P1603 (PCM Internal dual port RAM communication failure; P0882 (TCM Power input signal low); P0461 (Fuel level sensor A Circuit range/performance). Car has been operating normally for about a 7 weeks but am concerned that problem may return. Advised that transmission controller may need replacement. Your opinion is appreciated.

My car has 78079 miles.
My car has an automatic transmission.

Hello there, many different faults can cause this combination of codes on your 2006 Chrysler PT Cruiser.

When we see loss of communication codes with Transmission Control Module (TCM) internal faults, this usually means one of the following:

  • the TCM is failing
  • the TCM is not being supplied with enough power
  • the wiring to the TCM is faulty

Given that you have fuel codes as well, the first place a qualified technician should check is the battery, and to inspect the wiring of the vehicle. Then a Check Engine Light inspection should be done to asses the codes.

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