P2610

CIRCUIT DESCRIPTION
The DTC P1600 Control Module Long Term Memory Reset diagnostic detects a loss of battery voltage to the control module's keep alive memory circuit. Battery positive voltage is supplied to the powertrain control module (PCM) even when the ignition switch is OFF. The battery positive voltage is used for the PCM keep alive memory and the air-fuel ratio adaptive control memory. If DTC P1600 is set, the PCM will not store any other DTCs.

CONDITIONS FOR SETTING THE DTC
No battery voltage at the PCM battery positive voltage circuit.

ACTION TAKEN WHEN THE DTC SETS
- The PCM illuminates the malfunction indicator lamp (MIL).
- The PCM stores the conditions that were present when the DTC set as Freeze Frame data.

CONDITIONS FOR CLEARING THE MIL/DTC
- The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
- A DTC will clear after 40 consecutive warm-up cycles have occurred without a fault.
- A DTC can be cleared by using the scan tool Clear Information function.

TEST DESCRIPTION

Steps 1-5:

Steps 6-7:

The numbers below refer to the step numbers in the diagnostic table.
1. The Diagnostic System Check-Computers and Controls Systems prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. This step checks whether a DTC P1600 is the result of a hard failure or an intermittent condition.
3. This step checks for battery positive voltage at the electrical connector of fuse block-underhood. If the EFI fuse was faulty, or if there was no power to the fuse, the vehicle would not start and there would be no MIL or serial data communication.