P0067: Air Assisted Injector Control Circuit High
May cause rough idle, poor cold-start performance, reduced fuel economy and increased emissions; usually does not cause immediate driveability failure at normal operating temperature.
Overview
P0067 indicates the powertrain control module has detected a high voltage condition in the air assisted injector control circuit, often related to wiring, connectors, air assist injector solenoid or ECM issues.
Common Symptoms
- Check engine light illuminated
- Hard to start when cold
- Poor fuel economy
- Rough idle or misfire at cold start
- Reduced engine performance
Most Common Causes
Injector internal failure or stuck valve can drive circuit high.
Damaged insulation, chafing, or short to power/ground can elevate voltage readings.
Moisture, corrosion or bent pins cause high resistance and abnormal signals.
Rare but possible; misreads high voltage when internal driver fails.
Indirect influence on injector performance d in forums.
Diagnostic Steps
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Connect professional OBD-II scanner and confirm P0067, note freeze frame data.Expected: Persistent P0067 code; no other conflicting codes.Interpretation: Confirms exact fault and conditions when set.
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Visually inspect wiring harness and connectors for damage, corrosion, or loose contacts.Expected: No broken wires, exposed insulation, or corroded pins.Interpretation: Wiring/connectors are common causes; if faults present, repair.
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Test circuit voltage at air assisted injector control wire with ignition on (engine off).Expected: Voltage within manufacturer spec (often ~5V signal range).Interpretation: Above expected values indicates high circuit condition.
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Disconnect injector and measure coil resistance with multimeter.Expected: Resistance within OEM spec.Interpretation: Out-of-range suggests injector failure.
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If wiring and injector test good, evaluate PCM output or consider reprogram/replace.Expected: Proper driver output or confirmed PCM malfunction.Interpretation: PCM faults are less common but documented.
Repair Solutions
Most common and cost-effective fix; includes cleaning connectors and dielectric grease.
Part cost varies by make/model; test before replacement.
Only if driver circuit is confirmed faulty; requires VIN matching and programming.
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Assuming emission system MAP/MAF correlation issue (P0068) without verifying specific circuit voltage
- Replacing air assist injector without checking wiring/connectors first
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