E055

Code E055:

Sensor Circuit:

DESCRIPTION:

The TPS on the PFI is "self adjusting". At key off, the PCM/ECM executes a TPS learning routine. After key off, the PCM/ECM will retract the ISC until the ISC throttle switch opens and the throttle linkage is resting on the minimum air screw. At that time, the PCM/ECM stores the TPS value and calculates a correction. If the same correction factor occurs on two consecutive key "off" cycles, the TPS is then corrected to 0 degrees using the correction factor "learned". If the value needs correction by, more than -2.9 degrees or +3.0 degrees, code E055 will be stored in memory at the next key "ON" cycle.

NOTE: Parameter ED01, TPS, displays uncorrected TPS values.

TEST CONDITIONS:

1. No problems detected on the throttle position sensor or throttle switch circuits.
2. At key off the PCM/ECM will test for a misadjusted TPS, see DESCRIPTION.

FAILURE CONDITION:

"Learned" is less than -2.9° or greater than 3.0°.

ACTION TAKEN:

At the next key on, the PCM/ECM will log code E055 as current. No "Service" telltale or message will appear.

NOTES ON FAULT TREE:

1. Checking TPS adjustment. PCM/ECM parameter EDO1 TPS, displays uncorrected TPS so that it can be used to check TPS adjustment.

2. TPS adjustment is OK.

3. If TPS adjustment is OK, ISC and throttle switch operation need to be thoroughly checked. The throttle linkage needs to be checked for proper operation -- throttle, cruise and TV cables not binding, proper throttle return spring operation throttle shaft and blades free to move.

NOTE ON INTERMITTENTS:

Manipulate ISC wiring while observing PCM/ECM input EI72 and while observing ISC operation during PCM/ECM output Cycling E007. Manipulate TPS wiring and connector while observing PCM/ECM parameter EDO1 for jumps, skips, intermittent behavior. Check for TPS secured to throttle body (both TORX screws tight). Cycle the TPS through its full travel while observing EDO1 for erratic behavior. Check for proper part number TPS installed on vehicle. Remove and replace the TPS, ISC and PCM/ECM connectors and ensure that they are latched.