P0267

What Does Code P0267 Mean?

DTC P0267 signifies a detected electrical malfunction within the circuit controlling the fuel injector for cylinder number 3. The Engine Control Module (ECM), sometimes referred to as the Powertrain Control Module (PCM), continuously monitors the electrical characteristics of each fuel injector circuit. Specifically, for P0267, the ECM has identified a condition where the electrical resistance or voltage drop across the cylinder 3 injector circuit is lower than the manufacturer’s specified operational parameters, or it detects an open circuit, preventing sufficient current flow. This typically means the ECM is commanding the injector to activate, but it is not observing the expected current draw or voltage feedback, indicating a potential open circuit, excessive resistance, or a short to ground within the injector’s control circuit. This condition prevents cylinder 3’s injector from functioning correctly, directly impacting fuel delivery to that cylinder and consequently, engine performance and emissions.

Common Symptoms

• Check Engine Light (CEL) Illumination: The Malfunction Indicator Lamp (MIL) will be activated.
• Engine Misfire: Noticeable rough idle, hesitation, or stumbling, particularly under load.
• Reduced Engine Performance: Diminished power output and poor acceleration.
• Increased Fuel Consumption: The ECM may attempt to compensate for the misfire, leading to inefficient fuel use.
• Rough Idling: A distinct vibration or uneven engine operation at idle speeds.
• Difficulty Starting: In some severe cases, an extreme misfire can make starting difficult.
• Strong Fuel Odor: Unburnt fuel may exit the exhaust if the injector is completely non-functional or stuck open (less common for a “low” circuit unless it’s an internal short that leads to constant activation, which is usually a different code).

What Causes the Code P0267?

• Faulty Fuel Injector (Cylinder 3): An internal electrical fault within the injector itself, such as an open circuit in the coil winding or excessively high resistance, preventing proper current flow.
• Damaged Wiring Harness: An open circuit (break) in the wiring leading to the cylinder 3 fuel injector, a short circuit to ground, or severe chafing leading to intermittent contact.
• Corroded or Loose Connector: Oxidation, bent pins, or a poor connection at the electrical connector for the cylinder 3 injector or at the ECM harness connector.
• Poor Ground Connection: An insufficient or corroded ground path for the injector control circuit.
• Failed ECM/PCM Driver: Although less common, the fuel injector driver circuit within the ECM responsible for cylinder 3 may have failed, preventing it from supplying the necessary control signal.

How to Diagnose and Troubleshoot

Diagnosis of P0267 requires a methodical approach utilizing a digital multimeter (DMM) and an OBD-II scanner:

1. Retrieve Freeze Frame Data: Connect an OBD-II scanner and record all freeze frame data associated with P0267. This information provides crucial engine operating conditions at the time the fault was set, aiding in replication. Clear the DTCs after recording.
2. Visual Inspection: Perform a thorough visual inspection of the cylinder 3 fuel injector and its electrical connector. Examine the wiring harness from the injector back to the ECM for any signs of chafing, cuts, pinches, or corrosion. Check the injector connector for bent, pushed-back, or corroded terminals.
3. Fuel Injector Resistance Test: With the ignition OFF, disconnect the electrical connector from the cylinder 3 fuel injector. Using a DMM set to ohms, measure the resistance across the two terminals of the injector itself. Compare this reading to the manufacturer’s specifications (typically 10-18 ohms, but consult service data for your specific vehicle). An open circuit (OL or infinite resistance) or a reading significantly higher than specification indicates an internal fault within the injector.
4. Voltage Supply Test: With the cylinder 3 injector connector still disconnected, turn the ignition ON (engine OFF). Using the DMM set to DC volts, probe one terminal of the injector harness connector while grounding the other DMM lead to a known good chassis ground. One of the terminals should show battery voltage (approximately 12V). This is the power supply side. If no voltage is present, troubleshoot the power supply circuit back to its fuse or relay.
5. Control Circuit Integrity Test: Turn the ignition OFF. Reconnect the DMM leads to the injector harness connector, set to ohms. Measure resistance between the control terminal (the one that did NOT show 12V in the previous step) and the corresponding injector control terminal at the ECM harness connector (after disconnecting it from the ECM). An ideal reading is less than 5 ohms. An open circuit (OL) indicates a break in the wiring. Also, perform a short-to-ground test by measuring resistance between the control wire terminal at the injector connector and chassis ground. An ideal reading should be infinite resistance (OL). Any low resistance reading indicates a short.
6. Noid Light Test: If resistance tests pass, reconnect the ECM and injector. Connect a noid light into the cylinder 3 injector connector. Crank the engine (or start if possible). Observe the noid light. If it flashes, the ECM is attempting to control the injector. If it does not flash, the ECM is not providing the ground pulse, which could indicate an internal ECM issue or an unaddressed open circuit.
7. Wiggle Test: While observing live data for misfire counts on cylinder 3 (if the engine is running) or watching the noid light (if cranking), gently wiggle the wiring harness and connectors associated with cylinder 3. Intermittent changes in misfire count or noid light behavior can indicate a loose connection or chafed wiring.

Recommended Repairs and Solutions

Repairs for P0267 are directly contingent on the diagnostic findings:

• Replace Faulty Fuel Injector: If the resistance test of the injector itself reveals an open circuit or excessively high resistance, the fuel injector for cylinder 3 is likely the culprit and should be replaced. Always use an OEM-quality replacement.
• Repair or Replace Wiring Harness: If testing indicates an open circuit or a short to ground within the wiring, the damaged section of the harness must be repaired using appropriate automotive wiring repair techniques (soldering and heat shrink) or the entire harness section replaced.
• Clean or Replace Connectors: If corrosion or damage is found at the injector or ECM connectors, clean the terminals thoroughly using specialized electrical contact cleaner and a small brush. If pins are bent, missing, or excessively corroded, the connector body or individual terminals should be replaced.
• Address Poor Ground Connections: Ensure all engine and chassis ground points are clean, tight, and free of corrosion.
• ECM/PCM Replacement: Only consider ECM/PCM replacement as a last resort, after meticulously verifying all other components and circuits. This is a rare failure for this specific code. If an ECM driver is suspected, specialized diagnostic equipment (e.g., oscilloscope) may be needed to confirm the absence of a control signal from the ECM despite all input conditions being met. Note that ECM replacement often requires programming.

Mechanic’s Tip: After any repair, clear the DTCs and perform a comprehensive test drive under varying conditions, including those recorded in the freeze frame data, to ensure the fault does not return. Always verify that the engine runs smoothly and the MIL remains off.