SLIGHTLY HIGHER THAN NORMAL IDLE SPEED (MAY BE WIRING)

MODELS AFFECTED: 1983-1984 CIMARRONS

Some 1983-1984 Cimarrons may experience a customer complaint of excessive engine noise. The engine noise may be the result of a high engine idle speed of 1200 to 1625 rpm, that might occur during closed loop operation in park or neutral, with the steering wheel not in a full right or left position. The raised idle speed does not adversely affect vehicle driveability or performance.

The high idle speed may be caused by an open in the power steering pressure switch signal circuit to the ECM. 1983 and 1984 model Cimarrons use a normally CLOSED power steering pressure switch. An open in the signal line from this switch is interpreted by the ECM as high power steering load. The engine rpm will be raised accordingly. 1985 and later models use a normally OPEN power steering pressure switch.

To repair this condition, the following steps should be performed:

1. Test the vehicle in park with the engine at normal operating temperatures (closed loop operation) and the steering wheel in the straight ahead position.

2. Disconnect the power steering pressure switch.

3. Note any change in idle rpm.

- If the idle speed chanees, an open in the signal line is not the cause of the high idle speed. Normal diagnostic procedures should be followed to isolate the cause of the high idle speed.

- If the idle soeed does not change, an open in the signal line may be the cause of the high idle speed.

4. Refer to the 1983 Cimarron Service Information Manual, page 6E2-40A, or the 1984 Cimarron Service Manual, page 6E2-74, for a description of the wiring circuit. Isolate and repair any opens in the power steering pressure switch circuitry.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.