Operation CHARM: Car repair manuals for everyone.
Home >> GMC >> 1993 >> S15/T15 2WD P/U L4-151 2.5L >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Idle Speed/Throttle Actuator - Electronic >> Service and Repair
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Idle Speed/Throttle Actuator - Electronic: Service and Repair

NOTE
- Do NOT immerse in any type of liquid solvent or cleaner, as damage may occur.
- On this TBI unit, the IAC valve is flange mounted, with a dual taper, 10 mm diameter pintle. If replacement is necessary, only an IAC valve identified with the correct part number (having the appropriate pintle shape and diameter) should be used.

Flange Mounted IAC Valve:





REMOVE OR DISCONNECT
- Electrical connector from IAC valve.
- Screw assemblies and IAC valve.
- IAC valve o-ring and discard.

CLEAN
- Both original and replacement IAC valves have a special factory applied thread-locking compound applied to the screw threads. If the valve removed from throttle body is being reinstalled, DO NOT remove thread-locking that may remain on the threads.
- Clean IAC valve seating surfaces on throttle body to assure proper seal of new O-ring and contact of IAC valve flange.

Adjusting IAC Valve Pintle:





NOTES
- If IAC valve was removed during service, its operation may be tested electrically with the IAC/ISC Motor Tester (J-37027 or BT-8256K) or equivalent. Before installing IAC valve, measure the distance between the tip of valve pintle and mounting surface. If the dimension is greater than 28.0 mm (1.10 inches), valve pintle must be retracted to prevent damage to valve. This may be done electrically using an IAC/ISC Motor Tester or manually by exerting firm pressure, as shown in the illustration, with a slight side to side movement on valve pintle to retract it.
- No physical adjustment of IAC valve assembly is required after installation. The IAC valve pintle is reset by turning the ignition "ON" for ten seconds and then "OFF". The ECM then resets the pintle to the correct position. Proper idle regulation should result.

INSTALL OR CONNECT
- Lubricate new o-ring with transmission fluid and install on IAC valve.
- IAC valve to throttle body.
- IAC valve attaching screw assemblies that have been coated with appropriate thread locking compound. Tighten screw assemblies to 3.2 Nm (28.0 lb-in).
- Electrical connector to IAC valve.
- "START" engine and allow engine to reach operating temperature.
pro multis · About Operation CHARM