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 ).
5. Wiggle the harness(s) and connector(s) (see ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).