P01D2: Cylinder 4 Injection Timing Performance – Over Advanced
May cause rough idle, reduced power, misfire or increased emissions due to incorrect fuel injection timing on cylinder 4.
Overview
OBD-II P01D2 Cylinder 4 injection timing performance – over advanced; relates to injector timing on cylinder 4 being too advanced, often seen on GM Duramax and other engines with advanced timing learning.
Common Symptoms
- Illuminated check engine light (MIL)
- Rough idle or misfire on cylinder 4
- Decreased engine performance
- Reduced fuel efficiency
Most Common Causes
Injector mechanical or electrical issues can affect timing performance.
Related to ECM ‘learning’ values and crankshaft/camshaft sensors affecting timing calculation.
Poor electrical connection can skew injector timing signals.
Mechanical timing issues may influence perceived injector timing performance.
Diagnostic Steps
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Retrieve DTC and any related injector timing codes with OEM-level scan toolExpected: Code P01D2 present; potential other related injector codesInterpretation: Confirms injector timing fault on cylinder 4
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Inspect wiring and connectors to cylinder 4 injectorExpected: No broken wires, corrosion, or poor connectionsInterpretation: Wiring faults can mimic timing performance issues
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Perform injector balance or contribution test on cylinder 4Expected: Injector contribution and timing comparable to other cylindersInterpretation: Abnormal results suggest injector fault or timing problem
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Check crankshaft and camshaft position sensor signalsExpected: Accurate and stable timing signalsInterpretation: Incorrect sensor signals can affect timing calculations
Repair Solutions
Cost varies by injector type and labor rates.
Depends on extent of electrical repair.
May require dealer/advanced scanner.
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Fuel pressure regulator or general fuel delivery issue (confused with P0002/P0001 codes)
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