Check For Intermittent Problems

HINT:

Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect with the intelligent tester when the ECM is in check mode. In check mode, the ECM uses 1 trip detection logic, which is more sensitive to malfunctions than normal mode (default), which uses 2 trip detection logic.

1. Clear the DTCs (see DTC CHECK / CLEAR  ).
2. Switch the ECM from normal mode to check mode using the intelligent tester (see CHECK MODE PROCEDURE  ).
3. Perform a simulation test (see HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS ).
4. Check and wiggle the harness(es), connector(s) and terminal(s) (see ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).