DTC Troubleshooting: P16AC (0-42)

DTC P16AC:  ECM Internal Circuit Malfunction

1.Turn the ignition switch ON (II).

2.Reset the ECM with the HDS.

3.Turn the ignition switch OFF, and wait 30 seconds.

4.Start the engine. Hold the engine speed at 2,000 rpm (min-1) without load (in neutral) until the radiator fan comes on, then let it idle.

5.Test-drive under these conditions:
  • Engine coolant temperature above 80 °C (176 °F)
  • Transmission in 1st gear
  • Rise the engine speed to 4,000 rpm (min-1), then decelerate (with the throttle fully closed)

6.Check for Temporary DTCs or DTCs with the HDS.

Is DTC P16AC indicated?


YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.n


NO - Intermittent failure, system is OK at this time.n