NOTE: Atmospheric sensor is built into ECU. No circuit testing is required.

Turn ignition off. Remove BACK UP fuse from underhood fuse/relay box for 10 seconds to reset ECU. Check ECU for fault codes. See RETRIEVING CODES . If Code 13 is not present, problem is intermittent. Check for poor connections at ECU connector. Test drive vehicle and check again.
If Code 13 is present on M/T models, go to step 4). If Code 13 is present on A/T models, turn ignition off. Connect ECU Test Harness (07LAJ-PT3010A ) between ECU and ECU connector. See Figure . Disconnect 18-wire connector from A/T control unit. Check for continuity between test terminal D8 and body ground.
If continuity is present, repair short in Red/White wire between ECU connector terminal D8 and A/T control unit. If continuity is present, substitute a known good A/T control unit. If CHECK ENGINE light goes off and Code 13 is not present, replace original A/T control unit.
If CHECK ENGINE light stay on and/or Code 13 is still present, substitute a known good ECU. If symptom/condition goes away, replace original ECU. On M/T models, if Code 13 is present, substitute a known good ECU. If symptom/condition goes away, replace original ECU.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Code 13: Atmospheric (Pa) Sensor