Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSVOLVO2004S80 L6-2.9L TURBO VIN 91 B6294TREPAIR AND DIAGNOSISA L L DIAGNOSTIC TROUBLE CODES ( DTC )TESTING AND INSPECTIONMANUFACTURER CODE CHARTSECM CODES (ENGINE CONTROL MODULE)ECM-644ADIAGNOSTIC TROUBLE CODE (DTC) INFORMATION
2004 Volvo S80 L6-2.9L Turbo VIN 91 B6294T
Diagnostic Trouble Code (DTC) Information
2004 Volvo S80 L6-2.9L Turbo VIN 91 B6294TSECTION Diagnostic Trouble Code (DTC) Information
Diagnostic trouble code (DTC) information
Condition
The control module checks that the camshaft is in the correct position in relation to the position of the crankshaft. If the position of the camshaft is incorrect, the control module will adjust the adaptation for the camshaft. Diagnostic trouble code (DTC) ECM-643A or ECM-644A is stored if the adaptation becomes too great.
Substitute value
None.
Possible source
Signal too high
- Poor oil quality
- Incorrectly adjusted camshafts
- The timing gear belt has jumped off the cogs
- Defective reset valve
- Mechanical fault in the variable valve timing (VVT) unit.
Signal too low
- Poor oil quality
- Incorrectly adjusted camshafts
- The timing gear belt has jumped off the cogs.
Fault symptom[s]
- Malfunction indicator lamp (MIL) lit.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.