Possible Causes
WARNING: This page is about a different car, the 2003 Toyota 4Runner. However, it is still accessible from the selected car via links, so may be relevant.
DTC is set when A/F sensor output voltage does not change after engine is started with engine at normal operating temperature. This DTC uses two-trip detection logic. Possible causes are:
- A/F sensor (B1 & 2, S1) circuit is open or shorted.
- Defective A/F sensor (B1 & 2, S1).
- Defective A/F sensor heater (B1 & 2, S1).
- Defective A/F sensor heater relay and/or circuit.
- Air induction system malfunction.
- Improper fuel pressure.
- Defective fuel injector.
- Vehicle has run out of fuel.
- Defective ECM.