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GTECH Calibration
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P1689

No Communication Between ECM & Injection Pump Module.

  • Dodge
  • Powertrain
  • Manufacturer code
  • High severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
6
AreaComputer and output circuits
89
FaultThe specific fault in that area

What it means

On Dodge, P1689 means the engine control module has lost communication with the injection pump module (the fuel injection pump driver or controller on the diesel engine). The ECM expects regular data messages from the pump module and has stopped receiving valid ones, so it stores the fault. The exact module layout depends on the model and engine, so check the wiring diagram for your vehicle.

Symptoms

  • Engine cranks but will not start
  • Engine stalls or cuts out while running
  • Loss of power or limp-home behaviour
  • Engine management or check engine light on
  • Rough running or erratic fuelling
  • Other related fault codes stored for the pump or fuel system

Possible causes

  • Damaged, chafed or corroded wiring in the communication circuit between the ECM and injection pump modulelikely
  • Loose, corroded or water-damaged connectors at the ECM or injection pump modulelikely
  • Low battery voltage or poor power and earth supply to the injection pump modulepossible
  • Faulty injection pump module or pump driverpossible
  • Blown fuse or faulty relay feeding the pump module or ECMpossible
  • Faulty ECM or outdated ECM softwarerare

How to diagnose

  1. Read all stored codes and freeze frame data, noting any power supply, pump or other communication codes
  2. Check battery condition and charging voltage, as low voltage can interrupt module communication
  3. Inspect fuses and relays for the ECM and injection pump module and check they are sound
  4. Visually inspect the wiring and connectors between the ECM and pump module for chafing, heat damage, corrosion or moisture
  5. Check power and earth supplies at the injection pump module against the manufacturer's wiring diagram
  6. Test the communication circuit for continuity, short to earth and short to voltage with the connectors disconnected
  7. Check for any applicable software updates or service bulletins for your model and engine
  8. Only after the wiring and supplies are proven good, test or substitute the pump module and ECM as the procedure for your model directs

How to fix

  • Repair or replace damaged wiring in the communication circuit
  • Clean, repair or replace faulty connectors and terminals
  • Charge or replace a weak battery and correct any charging or earth faults
  • Replace blown fuses or faulty relays after finding the cause of the failure
  • Replace the injection pump module if it is confirmed faulty
  • Replace or reprogram the ECM only if it is confirmed faulty or an outdated calibration is a known cause

Can I keep driving?

High severity

Do not rely on the vehicle: it may stall or fail to restart, which is a safety risk in traffic. Have it diagnosed and repaired before further driving, other than a short careful trip to a safe place or workshop.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

This code for other makes

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