Test TC-25A: Idle Air Control Motor Circuits

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article.

Turn ignition off for 10 seconds. Start engine. Allow engine to idle for 20 seconds. If engine will not idle, hold throttle open slightly to keep engine running. Using scan tool, actuate Idle Air Control (IAC) motor to 1400 RPM. If engine speed is 1300-1500 RPM, go to next step. If engine speed is not 1300-1500 RPM, go to step 7) .
Using scan tool, actuate IAC motor to 900 RPM. If engine speed is 800-1000 RPM, go to next step. If engine speed is not 800-1000 RPM, go to step 7) .
Condition to set trouble code is not present at this time. IDLE AIR CONTROL MOTOR CIRCUITS DTC sets if Powertrain Control Module (PCM) senses a short to ground or battery voltage on any 4 IAC driver circuits for 2.75 seconds while IAC motor is active. Possible causes are: driver circuit shorted to ground, driver circuit shorted to battery, driver circuits shorted together, failed PCM, shorted IAC motor, faulty connections or wiring.
Inspect all related wiring and connectors and repair as necessary. If no problems were found with wiring and connectors, go to next step. If related wiring and connectors were repaired, perform TEST VER-2A .
Start engine. Allow engine to run until operating temperature is reached. Using scan tool, actuate IAC motor wiggle test. Idle speed should raise and lower with scan tool display. If IAC motor operates properly, go to next step. If IAC motor does not operate properly, go to step 7) .
Wiggle wiring harness from IAC motor to Powertrain Control Motor (PCM). If IAC motor stopped operating at any time, repair wiring harness as necessary where wiggling caused problem to appear. Perform TEST VER-2A . If IAC motor did not stop operating at any time, stop IAC motor wiggle test. See INACTIVE TROUBLE CODE CONDITION . Test is complete. Perform TEST VER-2A .
NOTE: For remaining test steps, see IAC DRIVER CIRCUIT IDENTIFICATION table for IAC motor connector wire color identification.
Using scan tool, stop all actuation tests. Turn ignition off. Disconnect IAC motor connector. Using an ohmmeter, check resistance of IAC driver No. 1 circuit between IAC motor connector and ground. If resistance is less than 5 ohms, repair short to ground in driver No. 1 circuit. Perform TEST VER-2A . If resistance is more than 5 ohms, go to next step.
Check resistance of IAC driver No. 2 circuit between IAC motor connector and ground. If resistance is less than 5 ohms, repair short to ground in driver No. 2 circuit. Perform TEST VER-2A . If resistance is more than 5 ohms, go to next step.
Check resistance of IAC driver No. 3 circuit between IAC motor connector and ground. If resistance is less than 5 ohms, repair short to ground in driver No. 3 circuit. Perform TEST VER-2A . If resistance is more than 5 ohms, go to next step.
Check resistance of IAC driver No. 4 circuit between IAC motor connector and ground. If resistance is less than 5 ohms, repair short to ground in driver No. 4 circuit. Perform TEST VER-2A . If resistance is more than 5 ohms, go to next step.
Reconnect IAC motor connector. Start engine and idle. Disconnect IAC motor connector. Using a voltmeter, check voltage of IAC motor connector driver No. 1 circuit. If voltage is more than 5 volts at any time, go to next step. If voltage is 5 volts or less at any time, go to TEST TC-25B .
check voltage of IAC motor connector driver No. 2 circuit. If voltage is more than 5 volts at any time, go to next step. If voltage is 5 volts or less at any time, go to TEST TC-25C .
check voltage of IAC motor connector driver No. 3 circuit. If voltage is more than 5 volts at any time, go to next step. If voltage is 5 volts or less at any time, go to TEST TC-25D .
check voltage of IAC motor connector driver No. 4 circuit. If voltage is more than 5 volts at any time, go to next step. If voltage is 5 volts or less at any time, go to TEST TC-25E .
Turn ignition off. Disconnect PCM connector. Inspect PCM connector for damaged or pushed out terminals. Repair as necessary. Perform TEST VER-2A . If connector is okay, go to next step.
Using an ohmmeter, check resistance between the following circuits at IAC motor connector. Record resistance readings.
- IAC motor connector driver No. 1 and driver No. 2
- IAC motor connector driver No. 1 and driver No. 3
- IAC motor connector driver No. 1 and driver No. 4
If resistance between any 2 wires was less than 5 ohms, repair those wires for shorting together. Perform TEST VER-2A . If resistance between all pairs of wires was 5 ohms or more, go to next step.
Using an ohmmeter, check resistance between the following wires at IAC motor connector. Record resistance readings.
- IAC motor connector driver No. 2 and driver No. 3
- IAC motor connector driver No. 2 and driver No. 4
If resistance between any 2 wires was less than 5 ohms, repair those wires for shorting together. Perform TEST VER-2A . If resistance between all pairs of wires was 5 ohms or more, go to next step.
Using an ohmmeter, check resistance between the following wires at IAC motor connector. Record resistance readings.
- IAC motor connector driver No. 3 and driver No. 4
If resistance between wires was less than 5 ohms, repair wires for shorting together. Perform TEST VER-2A . If resistance between wires was 5 ohms or more, replace IAC motor. Perform TEST VER-2A .

IAC DRIVER CIRCUIT IDENTIFICATION

Application

Wire Color

Avenger, Sebring Coupe & Talon

Driver No. 1

Gray/Dark Blue

Driver No. 2

Orange

Driver No. 3

Gray

Driver No. 4

Yellow/Dark Blue

Breeze, Cirrus, Sebring Conv. & Stratus (2.0L & 2.4L)

Driver No. 1

Gray/Red

Driver No. 2

Yellow/Black

Driver No. 3

Brown/White

Driver No. 4

Violet/Black

Cirrus, Sebring Conv. & Stratus (2.5L)

Driver No. 1

Gray/Red

Driver No. 2

Yellow/Black

Driver No. 3

⁽¹⁾Brown/White

Driver No. 4

Violet/Black

Neon

Driver No. 1

Gray/Red

Driver No. 2

Yellow/Black

Driver No. 3

Brown/White

Driver No. 4

Violet

⁽¹⁾	On Sebring Convertible, wire color is Brown/Gray.