DTC P0505: Idle Speed Control (ISC) System Malfunction
CAUTION:
ISC actuator is pre-adjusted at factory. DO NOT
remove from throttle body or disassemble.
- Start engine and allow it to reach normal operating temperature. Turn ignition off. Allow engine to cool. Observe ISC actuator plunger as ignition is turned on, then off. If plunger and throttle lever move, check TP sensor following procedures in DTC P0121 . If plunger and throttle lever did not move, go to next step.
- Turn ignition off. Remove ISC relay located in engine compartment relay box. See Figure
. Using an ohmmeter, measure resistance between specified terminals. See ISC RELAY RESISTANCE
table. If resistance is as specified, go to next step. If resistance is not as specified, replace ISC relay.ISC RELAY RESISTANCE
Between Terminals No. Ohms 1 & 2 Infinity 1 & 2 (1) Continuity 3 & 4 19-95 (1) With battery voltage applied to terminals No. 3 and 4. - Disconnect harness connector from ISC actuator. Using an ohmmeter, ensure continuity exists between terminals of ISC actuator, and not between either terminal and body of ISC actuator. If continuity is as specified, go to next step. Replace ISC actuator if continuity is not as specified.CAUTION: Ensure connections to ISC actuator terminals are made correctly and voltage is not applied to terminals for longer than one second. Damage to ISC actuator may occur.
- Connect four 1.5 volt batteries (6 volts) together in series. Ensure throttle lever is in contact with ISC actuator plunger. Using fused jumper wires, connect positive side of batteries to terminal No. 3 of ISC actuator. See Fig 1 or Fig 2 . Connect negative side of batteries to terminal No. 1. Plunger should extend. Reverse jumper wires. Plunger should retract. If operation is as specified, go to next step. If operation is not as specified, replace lower throttle body and ISC actuator as an assembly.
- Check Gray/Yellow wire and Gray/Black wire between PCM and ISC control relay for an open or short. Check Gray wire and Gray/Red wire between PCM and ISC actuator for an open or short. Repair as necessary. If wires are okay, replace PCM. Retest system.