Allison Automatic Transmission

ALLISON AUTOMATIC TRANSMISSION

DTC P0700

Circuit Description for Allison Automatic Transmission
The malfunction indicator lamp (MIL) request circuit, signals the engine control module (ECM) that the transmission control module (TCM) is requesting MIL illumination.

DTC P0700 is a type A DTC.

Conditions for Running the DTC
The engine is running.

Conditions for Setting the DTC
The TCM is requesting MIL illumination or the MIL request circuit is shorted to ground.

Action Taken When the DTC Sets
^ The control module illuminates the MIL when the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Conditions for Clearing the DTC
^ The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
^ A scan tool can clear the code from TCM history. The TCM automatically clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without failure.

Diagnostic Aids
^ Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:
^ A bent terminal
^ A backed-out terminal
^ A damaged terminal
^ Poor terminal tension
^ A chafed wire
^ A broken wire inside the insulation
^ When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.
^ You may have to drive the vehicle in order to experience a condition.

Test Description

Steps 1-7:

The number below refers to the step number on the diagnostic table.
1. If the TCM has DTCs set that are requesting MIL illumination, those DTCs must be diagnosed first.