Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Failure Management
When main sensor malfunctions are detected, ECM/PCM will enter fail-safe mode. Default values will be substituted in ECM/PCM calculations for faulty sensor as follows:
- Volume Airflow Sensor
ECM/PCM will use engine speed (crankshaft position sensor) and Throttle Position (TP) sensor signals to determine injector drive time and basic ignition timing. Idle Air Control (IAC) motor remains in a fixed position. - Intake Air Temperature (IAT) Sensor
Sets at a default of 77Β°F (25Β°C). - Throttle Position (TP) Sensor
Fuel injection amount will not increase during acceleration due to unreliable TP sensor signal. - Engine Coolant Temperature (ECT) Sensor
Sets at a default of 176Β°F (80Β°C). - Camshaft Position (CMP) Sensor
ECM/PCM will command injectors to inject fuel into cylinders in normal 1-3-4-2 order, but may not be synchronized with camshaft timing. - Barometric Pressure (BARO) Sensor
Sets at a default of 30 in. Hg (101 kPa). - Knock Sensor
Switches ignition timing from high octane to fixed at low octane. - Heated Oxygen Sensor (HO2S) Front
Closed-loop fuel control is not allowed. - Heated Oxygen Sensor (HO2S) Rear
Allows closed-loop fuel control using front HO2S signals. - Generator FR Terminal
Generator output suppression control of electrical load is not performed. - Communication Line With Transaxle Control Module (TCM)
Ignition timing retard control is inoperative when transaxle speeds change. - Misfire Detection
Fuel supply is stopped to cylinder if misfiring will damage catalytic converter.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
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