Code
P1691
CHRYSLER
P — Powertrain
Fuel Injection Pump Controller Calibration Failure
Views:
UK: 18
EN: 26
RU: 23
AI status
Completed
Completed
100%
Causes
- Corrupted or missing calibration data in the pump controller or PCM
- Failed or interrupted software update/reflash of pump controller or PCM
- Faulty fuel injection pump controller or integrated pump assembly
- Loss of communication between PCM and pump controller (CAN/bus wiring)
- Low battery voltage or poor power/ground during programming
- Aftermarket or incorrect replacement module with incompatible calibration
Symptoms
- Malfunction Indicator Lamp (MIL) or check engine light illuminated
- Restricted engine power or limp-home mode
- Engine may be hard to start or may not start
- Rough running or misfire-like symptoms under load
- Stored DTC(s) related to pump controller, CAN communication, or injector control
What to check
- Read and record all stored and pending DTCs and freeze frame data with a factory-capable scan tool
- Verify battery voltage (must be healthy and fully charged) and charging system operation
- Inspect wiring and connectors between PCM and pump controller for damage, corrosion, or loose pins
- Check for recent software updates, module replacements, or attempted reflashes noted in service history
- Confirm part numbers and calibration IDs of PCM and pump controller match manufacturer specifications
- Verify vehicle communicates with the pump controller over the diagnostic/CAN bus
Signal parameters
- Battery/supply voltage at pump controller: should be stable (typical >12 V with engine off; ~13.5–14.5 V with engine running)
- Controller ground integrity: low resistance to chassis ground
- CAN bus voltages: CAN High/Low ~2.5 V idle and differential signalling present during communication
- Pump controller status messages present/absent (requires factory tool to view calibration ID and status)
- Command vs feedback signals for pump control (PWM duty/frequency and any reported fuel pressure or position feedback)
Diagnostic algorithm
- Connect a professional scan tool and retrieve all codes, freeze frame, and current/calibration data for PCM and pump controller.
- Confirm battery state of charge and ensure stable supply voltage. Recharge or replace battery if low.
- Inspect physical connectors and wiring for damage, corrosion, or poor pins between PCM, pump controller, and power/ground. Repair as needed.
- Verify CAN/diagnostic communication with the pump controller. If no communication, isolate wiring or bus faults before continuing.
- Check for mismatched or incorrect module part numbers or calibration IDs. Compare against manufacturer build data.
- If wiring and power/communication are good, attempt to clear the DTC and perform a controlled re-test to reproduce the fault.
- If the code persists and the controller is reachable, follow manufacturer service procedure to reflash or reprogram the pump controller/PCM calibration using the factory scan tool. Ensure battery is fully charged and follow recommended soak/time procedures.
- If reprogramming fails or the controller reports internal errors, replace the pump controller or pump assembly per manufacturer instructions and program new calibration as required.
- After repair or reflash, erase codes and perform road test/verification. Re-scan to ensure no related codes remain and calibration IDs are correct.
- If problem continues, escalate to dealer or manufacturer technical support for known software updates or service bulletins.
Likely causes
- Pump controller hardware failure
- Failed reflash or interrupted calibration procedure
- Connector corrosion or damaged wiring in communication/power circuits
- Mismatched software/part number after a service replacement
- Weak battery or charging system causing programming errors
Fault status
Status
Fuel Injection Pump Controller calibration invalid or failed verification. PCM detected missing/mismatched calibration or failed programming of pump controller.
Repair difficulty: Hard
Diagnostic time: 2.0-6.0 hours
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