ZF 4HP 16 - Automatic Transmission (Non-Europe or N. American Emissions)

DTC P1606 (Non-Europe or N. American Emissions)

Circuit Description

In case the transmission control module (TCM) reset has occurred by software (warm reset) and not by ignition key ON, the TCM increments software resets the counter. If the counter exceeds the permissible maximum value for the software count, then the fault will be detected.

Conditions for Setting the DTC

* 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 hold lamp will blink.
* 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.
* Power supply cut off to the pressure control solenoid (PCS) valve.

Conditions for Clearing the Hold Lamp/DTC

* The hold lamp 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.