ECM - Code E055 Cannot Be Cleared: Overview

Bulletin No. T 87-132
File in Group 6E
Number 48
Corp. Ref. No. 716505
Date July '87
SUBJECT: ECM CODE E055

MODELS AFFECTED: 1987 ALLANTE

Some 1987 Allante vehicles may set a current ECM Code E055 (TPS misadjusted) that cannot be cleared using ECM clear codes in diagnostics. To clear a current Code E055 on an Allante the negative battery cable must be disconnected for 10 seconds.

It is important that the cause for a history or current code E055 be found using the trouble tree provided in this bulletin. The trouble tree will determine if the Code E055 was set due to:

1. Misadjusted cruise control cable.
2. Throttle body primary blade deposits (coking).
3. Misadjusted TPS.

Repair procedures for each of these causes is also included in this bulletin.

The ECM tests for a code E055 when the ignition is turned off. The ECM then retracts the ISC motor until the throttle rests on the minimum air screw. The ECM looks at TPS voltage to determine if the TPS is misadjusted. Two consecutive ignition off cycles with TPS voltage outside of a calibrated range (+/- 3~) will set code E055. The ECM won't test for code E055 unless the engine has been running for 10 minutes with the coolant temperature above 70~C during the ignition cycle. Therefore, the ECM will keep a code E055 current even if the ECM codes are cleared in diagnostics. The negative battery cable must be disconnected for 10 seconds (reset ECM memory) to clear a current code E055.

DIAGNOSTICS CHART:

DIAGNOSTICS CHART