CODE 27, IDLE SPEED FLUCUATE INFORMATION

THROTTLE SWITCH DOES NOT CLOSE - 1981-1982 DFI EQUIPPED CADILLACS

Some 1981-1982 Cadillacs equipped with Digital Fuel Injection may experience a throttle switch which does not close at closed throttle under certain operating conditions. Possible symptoms may include a fluctuation in idle speed within the range of speeds controlled by the ISC motor, a code 27, or failure to pass switch test 72 in DFI diagnostics. Replacement of the throttle return spring, with spring P/N 1626134 available through GMWDD, may correct this condition by providing additional force to close the throttle switch in the closed throttle position.

With the engine at normal operating temperature and the engine running, use switch test 72, as described in the 1982 Service Information Manual and 1981 Cadillac Digital Fuel Injection and Computer Command Control Diagnosis Manual Supplement to diagnose a throttle switch which does not close. On 1981 DFI vehicles, verify that the throttle spring anchor bracket is oriented in the proper direction as indicated in Figure 1.

CAUTION:

Throttle springs must not be bent, stretched, reshaped, or shorted, and throttle springs other than those specified must not be used. Use of an improper or modified throttle spring may result in a broken or ineffective throttle return.

Lubrication of the throttle cable or linkage is not necessary and is not recommended.

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.