System Check

WARNING: This page is about a different car, the 1992 Cadillac Brougham. However, it is still accessible from the selected car via links, so may be relevant.

Turn ignition switch to RUN position. Enter ECC diagnostic mode. See ENTERING DIAGNOSTIC MODE. If ECC Code 50 is set, perform ECC CODE 50 (LOSS OF EVO STEERING) test. If no codes are set, or if ECC Code 150 is set, check for ECM Code 24.
If ECM Code 24 is set, check Vehicle Speed Sensor (VSS) and its circuit. See the appropriate G - TEST W/ CODES article in the ENGINE PERFORMANCE section. Refer to the following menu. If ECM Code 24 is NOT set, turn ignition off. Remove 3-amp C/C fuse from engine compartment fuse block. Turn ignition switch to RUN position. Enter ECC diagnostic mode. While observing AUTO fan status light, install C/C fuse.
- Models with 5.0L V8, see: TESTS W/CODES - 5.0L TBI
- Models with 5.7L V8, see: TESTS W/CODES - 5.7L TBI
If AUTO fan status light did not come on momentarily, perform EVO INPUT TEST . If AUTO fan status light came on momentarily, raise and support rear of vehicle with wheels off ground. Connect "Scan" tester. Select EVO DUTY CYCLE. Start engine. Place transmission in gear. Accelerate to 50 MPH.
If duty cycle does not increase as vehicle speed increases, perform EVO INPUT TEST . If duty cycle increases as vehicle speed increases, compare steering effort while test driving vehicle at high speed with C/C fuse first removed, and then installed.
With fuse installed, if steering effort did not increase as vehicle speed increased, problem is mechanical. See the article STEERING SYSTEM - POWER in the this section. With fuse installed, if steering effort increased as vehicle speed increased, system is okay. If Code 150 was set as indicated in step 1), an intermittent problem may exist.