P0202
Injector Circuit/Open - Cylinder 2
If your vehicle's onboard computer has flagged the diagnostic trouble code P0202, it refers to a detected anomaly regarding "Injector Circuit/Open - Cylinder 2". This systemic engine fault needs a targeted check before symptoms expand.
Driver's Summary
P0202 is triggered when the PCM detects an abnormal condition associated with injector circuit/open - cylinder 2. You may notice vibration under load, misfire, poor fuel economy, all of which are direct consequences of this malfunction. Given the high severity of this code, continuing to drive risks significant mechanical damage. Have it diagnosed immediately.
Symptoms
Vibration under load, misfire, poor fuel economy
Common Causes
- Failed fuel injector on Cylinder 2
- Corroded injector connector
- Open circuit in injector wiring harness
- PCM failure
How to Fix
- 1 Replace fuel injector
- 2 Clean and tighten connector pins
- 3 Repair open wire
- 4 Replace or reflash PCM
Technical Explanation
To set P0202, the PCM samples the affected circuit multiple times per second, comparing live readings against manufacturer-programmed operating windows. Misfire rate is counted per cylinder over rolling windows and compared against two thresholds: a catalyst-damaging rate (triggers flashing MIL) and an emissions-exceeding rate (triggers solid MIL). The PCM logs which cylinder is misfiring based on crankshaft position at the time of each detected event. After two failed drive cycles, the code transitions from a pending to a confirmed DTC, and the PCM activates the MIL. Clearing the code without repairing the fault will result in re-illumination within one to two complete drive cycles.
Is It Safe to Drive?
An active P0202 code under high-severity conditions means the affected system is operating outside safe parameters. Continued driving — especially under load or at highway speeds — significantly increases the risk of secondary damage to components like corroded injector connector.
Mechanic's Pro Tip
Module replacement should always be the last resort for P0202 after exhaustively verifying all power supply circuits, ground connections, and communication bus wiring. Use a wiring diagram to locate all fuses, relays, and ground points for the affected module, and measure voltage drop on each ground with the circuit loaded. A module "failure" is frequently a corroded ground eyelet or a weak battery causing brownout conditions — fix these first and you'll save hundreds of dollars on an unnecessary module replacement.
Injector replacement: $150 - $400