Diagnostic Aids

Perform this test only when directed here. This test is intended to diagnose the following:

• Idle switch.
• Idle switch circuits.
• PCM.

1. DTC 0510: Check Idle Switch Continuity
   
   Turn ignition off. Disconnect idle switch harness connector. Ensure throttle is closed. Measure resistance between IDL terminal and IGN terminal on idle switch. See CIRCUIT PIN IDENTIFICATION  table. See Fig 1. If resistance is less than 50 ohms, go to next step. If resistance is not less than 50 ohms, replace idle switch.
   Fig 1: Identifying Idle Switch Circuits & Harness Connector Terminals

   Courtesy of FORD MOTOR CO.
2. Check IDL Circuit For Open
   
   Disconnect PCM harness connector. Measure resistance of IDL circuit between idle switch harness connector and PCM connector. If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, repair open in circuit.
3. Check IDL Circuit For Short To Ground
   
   Measure resistance between ground and IDL circuit at PCM harness connector. If resistance is greater than 10 k/ohms, go to next step. If resistance is not greater than 10 k/ohms, repair short in circuit.
4. Check IDL Circuit For Short To Power
   
   Measure resistance between IDL and VPWR circuits at PCM harness connector. If resistance is greater than 10 k/ohms, replace PCM. If resistance is not greater than 10 k/ohms, repair short in circuit.