P200F - Catalyst System Over Temperature (Bank 2)
System
Powertrain (Engine & Gearbox)
Technical Description
The control module has detected a fault in the Catalyst System Over Temperature (Bank 2) (P200F). Affects cylinder bank 2 (bank 2, radiator/left side).
Multimeter Test Points & Nominal Values
| Test Point / Component | Measurement | Nominal Target Range | Test Condition |
|---|---|---|---|
| Catalyst System Over Temperature (Bank 2) – Heater Resistance (Cold) | Resistance (Ω) | 2.5 - 10.0 Ω | Disconnected plug at 20°C |
| Catalyst System Over Temperature (Bank 2) – Signal Voltage | Voltage (V) | 0.10 - 0.90 V, oscillating 1 - 3 Hz | Warm engine closed loop at 2000 RPM |
| Catalyst System Over Temperature (Bank 2) – Pump Current (Wideband) | Current (mA) | -2.0 to +2.0 mA (0 mA at lambda 1.0) | Warm engine, closed loop |
Disconnected plug at 20°C
Warm engine closed loop at 2000 RPM
Warm engine, closed loop
Oscilloscope Waveform Analysis
1 s/div, 200 mV/divPossible Causes
Catalyst System Over Temperature (Bank 2) is electrically operational but performing outside calibrated tolerance
Bank 2 specific:Inspect wiring harness to cylinder bank 2 (radiator/left bank, exposed to vibration and moisture).
Chafed or pinched wiring harness along the signal path to Catalyst System Over Temperature (Bank 2)
Poor ground connection or excessive voltage drop (> 0.1 V) at the ground point for Catalyst System Over Temperature (Bank 2)
Defective internal output driver or reference circuit in the control module for Catalyst System Over Temperature (Bank 2)
Symptoms
4
Recommended Solution
Cross-swap the component on Bank 2 with Bank 1 to rule out mechanical oil passages and internal timing wear.
Verify underlying mechanical operation and rule out blockage, vacuum leaks, or mechanical binding.
Verify loaded supply voltage and harness terminal pins at Catalyst System Over Temperature (Bank 2).
Check circuit continuity and ground-side voltage drop (< 0.05 V) for Catalyst System Over Temperature (Bank 2).
For wideband sensors:monitor pump current (mA) and lambda in scan Live Data during snap-throttle and decel fuel cut.
Mechanic's Tip
O2 sensors measure free oxygen, not fuel. An exhaust leak upstream of the sensor pulls in atmospheric air via venturi pulses, forcing false lean readings and causing the ECM to severely over-fuel.