Power Steering Pressure Switch - High Idle Speed

88chevy30

Number: 84-273-6E

Section: 6E

Date: Nov., 1988
Subject: SLIGHTLY HIGHER IDLE SPEED


Model and Year: 1983-84 CAVALIER WITH 2.0L TBI (VIN CODE P) ENGINE AND POWER STEERING
TO: ALL CHEVROLET DEALERS


Condition:

Idle speed in the range of 1200 to 1625 RPM, in closed loop, in park or neutral, with the steering wheel not fully locked either right or left, may be experienced. This slightly raised idle speed has no adverse affect on driveability or vehicle performance, but may be objectionable from a noise standpoint.
Cause:

An open circuit in the signal to the Electronic Control Module (ECM) from the power steering pressure switch. Unlike the 1985 and later models which use a normally OPEN switch, the 1984 and earlier J-cars with the 2.0L engine use a normally CLOSED power steering pressure switch. If the ECM sees an open at any point in this circuit, it will interpret the open as a power steering load, and will raise the idle speed.
Correction:

Disconnect the power steering switch. If there is no change in idle speed, this condition is the cause of slightly higher idle and the switch should be replaced. If the idle speed changes, the cause of the higher idle speed should be investigated through normal diagnostic methods.
Refer to the 1984 Service Manual, pages 6E2-76 and 77, which is the Idle Air Control (IAC) Diagnostic Chart. The wiring diagram will lead to possible areas which may be open in the circuit, such as an open power steering pressure switch, an open A/C compressor clutch coil, an open A/C high pressure switch, an unplugged connector, loose ground connections, or a cut or pinched wire. Repair as necessary.