Fuel Injection Pump Controller Calibration Error (Dodge)
What does P1691 mean?
The P1691 code means the vehicle's onboard diagnostic system has detected: Fuel Injection Pump Controller Calibration Error (Dodge). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Reduced engine power
- Rough idle
- Excessive black smoke from exhaust
- Poor fuel economy
Probable Causes (Ranked by Likelihood)
- VP44 injection pump controller needs recalibration Very High
- Incorrect ECM software version for pump High
- VP44 internal wear causing calibration drift Moderate
- Failed VP44 injection pump controller Low
Step-by-Step Diagnostic Procedure
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Read injection pump calibration data with a Cummins-compatible scan tool.
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Verify the ECM software is the latest version compatible with the installed VP44 pump.
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Check if the VP44 was recently replaced with a different version that requires ECM recalibration.
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Monitor injection timing and fuel quantity values at idle and compare to specifications.
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If the pump cannot be recalibrated, it may need replacement due to internal wear.
Frequently Asked Questions
What causes a calibration error?
It typically occurs after a VP44 replacement if the new pump version does not match the ECM calibration, or from internal pump wear over time.
Can a dealer fix this with software?
Sometimes yes. The dealer can update the ECM calibration to match the installed pump. However, if the pump is worn internally, recalibration will not help.
Does this affect emissions?
Yes. An improperly calibrated injection pump can cause excessive smoke, poor fuel economy, and elevated emissions.