P201A - Reductant Injection Valve Range/Performance (Bank 2 Unit 1)
System
Powertrain (Engine & Gearbox)
Technical Description
The control module has detected a fault in the Reductant Injection Valve Range/Performance (Bank 2 Unit 1) (P201A). The reported signal is electrically valid but disagrees with other operating parameters (RPM, load, or other sensors). Affects cylinder bank 2 (bank 2, radiator/left side).
Multimeter Test Points & Nominal Values
| Test Point / Component | Measurement | Nominal Target Range | Test Condition |
|---|---|---|---|
| Reductant Injection Valve Range/Performance (Bank 2 Unit 1) – Coil Resistance | Resistance (Ω) | 3 - 30 Ω (typical) | Connector disconnected at 20°C |
| Reductant Injection Valve Range/Performance (Bank 2 Unit 1) – Duty Cycle | PWM (%) | 5 - 95 % (modulates with target) | Engine running, actuator in control |
| Reductant Injection Valve Range/Performance (Bank 2 Unit 1) – Supply Voltage | Voltage (V) | 11.8 - 14.4 V | Ignition ON at connector |
Connector disconnected at 20°C
Engine running, actuator in control
Ignition ON at connector
Oscilloscope Waveform Analysis
2 ms/div, 20 V/divPossible Causes
Reductant Injection Valve Range/Performance (Bank 2 Unit 1) 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 Reductant Injection Valve Range/Performance (Bank 2 Unit 1)
Internal mechanical wear or carbon deposits inside Reductant Injection Valve Range/Performance (Bank 2 Unit 1)
Defective internal output driver or reference circuit in the control module for Reductant Injection Valve Range/Performance (Bank 2 Unit 1)
Symptoms
4
Recommended Solution
Cross-swap the component on Bank 2 with Bank 1 to rule out mechanical oil passages and internal timing wear.
Log component live data across varying load points and verify plausibility against engine target model.
Verify loaded supply voltage and harness terminal pins at Reductant Injection Valve Range/Performance (Bank 2 Unit 1).
Check circuit continuity and ground-side voltage drop (< 0.05 V) for Reductant Injection Valve Range/Performance (Bank 2 Unit 1).
Check supply and the low-side driver at the ECM connector. Replace the actuator or repair the circuit based on the readings.
Mechanic's Tip
Use the scan-tool output test with the scope on the control side at the same time. If duty changes but the actuator does not move, the valve is stuck — not the electrical fault you were chasing.