2003 Toyota T&C Multiple OBD2 Codes: P0106, P0107, P0108, P0122, P1478, P1598 - Diagnosis and Fixes
I'm experiencing persistent OBD2 fault codes on my 2003 Toyota T&C: P0106, P0107, P0108, P0122, P1478, and P1598. All other codes clear after resetting the system, but these remain active. I've already replaced the catalytic converter and both oxygen (O2) sensors. Battery and alternator tests show no issues. No vacuum leaks have been detected during inspection. The vehicle exhibits inconsistent performance, particularly at idle. I'm seeking expert input on possible root causes or diagnostic steps to resolve this issue.
P0106, P0107, and P0108 are typically related to the Manifold Absolute Pressure (MAP) sensor. P0122 points to a Throttle Position Sensor (TPS) issue. P1478 indicates a battery temperature sensor fault. P1598 relates to an AC transducer problem. Try disconnecting each sensor one at a time and monitor voltage readings. A faulty AC or TPS is likely—start with the AC sensor first. Sorry, I'm currently busy but will provide more details later.