ZF 4HP 16 - Automatic Transmission (European and N. American Emissions)

DTC P0604 (European and N. American Emissions)

Circuit Description

A normal function of the transmission control module (TCM) programming is to perform an internal check that verifies the integrity of the random access memory (RAM) memory allocations.

The DTC P0604 sets when the RAM is not operating correctly when checked on initialization. An area of RAM is failed a read/write test.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0604 Transmission Control Module (TCM) Random Access Memory (RAM)

Conditions for Setting the DTC

* An area of RAM has failed a read/write test.
* System voltage is too high or too low.
* Transaxle input voltage is too high or too low.
* Immediately after the above condition occurs

Action Taken When the DTC Sets

* The malfunction indicator lamp (MIL) will illuminate.
* The TCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records buffer.
* Adopt Emergency/Substitute mode and constant 4th gear by hydraulic control.
* After ignition OFF/ON : 3rd gear by hydraulic control. P, R and N also possible.
* Power supply cut off to the pressure control solenoid (PCS) valve.

Conditions for Clearing the MIL/DTC

* The MIL will turn OFF when the malfunction has not occurred after 3 ignition cycles.
* A history DTC will clear after 40 consecutive warm-up cycles without a fault.
* Using a scan tool can clear history DTCs.

Diagnostic Aids

When DTC P0604 sets, the replacement of TCM is recommended.