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Home >> Acura >> 2003 >> 3.2CL Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Performance System Self-Diagnostics >> Diagnostic Tests >> DTC P1678: Frame-To-Powertrain Torque Down Request Signal Line Malfunction (A/T Models Only)
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DTC P1678: Frame-To-Powertrain Torque Down Request Signal Line Malfunction (A/T Models Only)

  1. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Start engine and wait 60 seconds. If DTC P1678 is set, go to next step. If DTC P1678 is not set, problem is intermittent. System is okay at this time. Check for poor connection(s) or loose wire(s) between PCM 20-pin "E" harness connector and ABS/TCS control unit 16-pin harness connector.
  2. Turn ignition switch off. Disconnect ABS/TCS control unit 16-pin harness connector. Start engine and wait 10 seconds. If DTC P1678 is set, substitute known-good ABS/TCS control unit, then recheck. If symptom or indication goes away, replace original ABS/TCS control unit. If DTC P1678 is not set, substitute known-good PCM, then recheck. If symptom or indication goes away, replace original PCM.
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