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Home >> Kia >> 2002 >> Optima SE, 2.7 8 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 2.7L >> Diagnostic Tests >> DTC P1602: Serial Communication Problem With Transaxle Control Module (Time-Out) >> Test Procedure
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Test Procedure

  1. Turn ignition off. Disconnect ECM harness connector "F". See Figure. Disconnect TCM harness connector "C". See Fig 1. Measure resistance between ECM connector terminal F36 and TCM connector terminal C3 (Orange/Black wire). Also measure resistance between ECM connector terminal F37 and TCM connector terminal C4 (Tan/Black wire). Both resistances should be below one ohm. If resistances are as specified, go to next step. If any resistance is not as specified, repair open circuit as necessary and go to step  6.
  2. With ECM harness connector and TCM harness connector disconnected. Measure resistance between ground and ECM connector terminal F36 (Orange/Black wire). Also measure resistance between ground and ECM connector terminal F37 (Tan/Black wire). Both resistances should be infinite. If resistances is as specified, go to next step. If any resistance is not as specified, repair short as necessary and go to step  6.
  3. With ECM harness connector and TCM harness connector disconnected. Turn ignition on. Measure voltage between ground and ECM connector terminal F36 (Orange/Black wire). Also measure voltage between ground and ECM connector terminal F37 (Tan/Black wire). Both voltages should be below 0.5 volts. If voltages are as specified, go to next step. If any voltage is not as specified, repair short as necessary and go to step. 6
  4. Turn ignition off. With ECM harness connector and TCM harness connector disconnected. Measure resistance between ECM connector terminal F36 (Orange/Black wire) and ECM connector terminal F37 (Tan/Black wire). Resistance should be infinite. If resistance is as specified, go to next step. If resistance is not as specified, repair short circuit as necessary and go to step  6.
  5. Thoroughly check for loose, bent or corroded connectors terminals at ECM and TCM connectors. If ECM and TCM connectors terminals are okay, go to next step. If ECM and TCM connectors terminals are faulty, check TCM related code. See appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS. Repair as necessary and go to next step.
  6. After repair, return vehicle to original condition. Clear codes using Hi-Scan Pro/Kia Data Pro Scan tool or equivalent. Verify repairs by driving vehicle and monitoring for pending codes. If DTC is set during test drive, follow appropriate DTC test procedure.
Fig 1: Identifying Transmission Control Module Connector Terminals
G00057027Courtesy of KIA MOTORS AMERICA, INC.
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