P1640

Steps 1 - 6:

DTC P1640 Output Driver Module (ODM) A Fault

Action Taken When the DTC Sets
- The PCM will not illuminate the malfunction indicator lamp (MIL).
- The PCM will store conditions which were present when the DTC was set as Failure Records only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC
- A history DTC P1640 will clear after 40 consecutive warm-up cycles occur without a fault.
- DTC P1650 can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids
Check for the following conditions:
- Poor connection at PCM - Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.
- Damaged harness - Inspect the wiring harness for damage, If the harness appears to be OK, disconnect the PCM, turn the ignition ON and observe a voltmeter connected to the suspect driver circuit at the PCM harness connector while moving connectors and wiring harnesses relates to the MIL. A change in voltage will indicate the location of the fault.
- Poor connection at component - Examine for damaged connectors, unplugged connector, or damaged terminals at the following locations: canister purge solenoid, Fuel level check. An open ignition feed circuit at any of these components will cause DTC P1650 to be set.

Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

The following PCM pins are controlled by output driver modules (ODMS):
- A13: MIL (Check Engine)
- A14: Check T/M or Up-shift
- A15: EVAP Canister Purge
- A16: Band Apply (4L30E)
- B14: A/C Clutch
- B15: Low Fuel Lamp
- B16: CCP Solenoid and VIM

Steps 7 - 13:

Steps 14 - 15:

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Chart.
4. The Tech 2 Driver Module Status indicates the PCM pin that is affected.
9. The Tech 2 may indicate short circuit even when the problem is an open circuit. The cause of an open circuit may be in the component itself.
11. A short to ground on the ignition side of the component will blow the fuse. Since the fuse was checked in Step 2, a short to ground would be between the affected component and the PCM.