Note On Intermittents

Enter diagnostics. Manipulate ISC wiring while observing OFF throttle switch status light and ISC operation during PCM output cycling. Manipulate TP sensor wiring and connector while observing PCM parameter P.0.1 for jumps, skips and intermittent behavior.

Check for TP sensor secured to throttle body (both Torx screws tight). Cycle TP sensor through its full travel while observing P.0.1. Check for proper part number TP sensor installed on vehicle. Disconnect and reconnect TP sensor, ISC and PCM connectors; ensure they are latched. If all circuits are okay, substitute a known good TP sensor, and retest.

Fig 1: PCM Code E55 Schematic - TP Sensor Out Of Adjustment

Courtesy of GENERAL MOTORS CORP.

Fig 2: PCM Code E55 Flow Chart - TP Sensor Out Of Adjustment

Courtesy of GENERAL MOTORS CORP.