DTC P0505: Idle Air Control Motor Circuits: Testing
- Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed and equal to zero, go to next step. If GOOD TRIP counter is not displayed and equal to zero, go to step 8 .
- Turn ignition off. Disconnect IAC motor harness connector located on side of throttle body, below Throttle Position (TP) sensor. Disconnect PCM harness connectors. See Figure . Measure resistance between IAC driver circuit No. 1 (Gray/Red wire) each of the remaining driver circuits at IAC motor harness connector. See Fig 1 . If resistance is 5 ohms or more between all driver circuits, go to next step. If resistance is less than 5 ohms between any driver circuits, repair short between driver circuits.
- Measure resistance between IAC driver circuit No. 2 (Yellow/Black wire) and driver circuits No. 3 (Brown/White wire) then No. 4 (Violet/Black wire) at IAC motor harness connector. If resistance is 5 ohms or more between all driver circuits, go to next step. If resistance is less than 5 ohms between any driver circuits, repair short between driver circuits.
- Measure resistance between IAC driver circuit No. 3 (Brown/White wire) and No. 4 (Violet/Black wire) at IAC motor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short between driver circuits.
- Remove Auto Shutdown (ASD) relay from Power Distribution Center (PDC). See Figure and Figure . Connect a fused jumper wire between ASD relay harness connector terminals "B" (Red/White wire) and "D" (Dark Green/Orange wire). Turn ignition on. Measure voltage between ground and each driver circuit at IAC motor harness connector. If voltage is one volt or less on all driver circuits, go to next step. If voltage is more than one volt on any driver circuit, repair short to voltage on driver circuit(s).
- Turn ignition off. Remove jumper wire. Measure resistance between ground and each driver circuit at IAC motor harness connector. If resistance is 5 ohms or more on all driver circuits, go to next step. If resistance is less than 5 ohms on any driver circuit, repair short to ground on driver circuit.
- Reconnect PCM harness connectors. Reinstall ASD relay in PDC. Start engine and let it idle. Connect a test light between ground and each driver circuit at IAC motor harness connector for 10 seconds. If test light turns on and off on each driver circuit, replace IAC motor. If test light does not turn on and off on each driver circuit, replace PCM.
- Conditions that set DTC are not present at this time. Perform the following to help identify intermittent condition:
- With engine running at normal operating temperature, wiggle related wiring harness while monitoring related parameters on scan tool. If voltage changes or DTC sets while wiggling wiring harness, repair connectors or wiring harness where wiggling caused voltage to change or DTC to set.
- Review freeze frame information on scan tool. Duplicate conditions present when DTC was set.
- Refer to any technical service bulletins that may apply.
- Visually inspect related wiring harness. Check for chafed, pierced, pinched or partially broken wires.
- Visually inspect related wiring harness connectors. Check for broken, bent, pushed out or corroded terminals.
If a problem is found, repair as necessary. If no problems are found, test is complete.