Diesel Trouble Codes

P1689 — No Communication Between ECM and Injection Pump Module — 5.9 Cummins 24-Valve (VP44)

The ECM has lost communication with the VP44 pump's controller. On the 5.9L 24-valve this commonly causes a no-start or stall and points to the ECM-to-pump…

Updated October 15, 2026

What it means

Manufacturer-enhanced code: the ECM has lost communication with the VP44 pump’s controller. On the 5.9L 24-valve this commonly causes a no-start or stall.1

Most likely causes

  1. ECM-to-VP44 data wiring or connector fault — Corrosion, pin damage, or chafing on the data link between the ECM and the pump-mounted controller interrupts communication.1
  2. VP44 power or ground fault — Loss of supply voltage or ground at the pump-mounted controller prevents the ECM from communicating with the VP44.1
  3. Battery or charging system weakness — Low system voltage can drop the VP44 controller offline, causing a communication loss with the ECM.1
  4. VP44 pump-mounted controller failure — Internal failure of the VP44 controller can stop communication with the ECM.1
  5. ECM internal fault — An internal ECM fault can prevent it from communicating with the VP44 controller.1

How to diagnose

  1. Verify battery voltage and charging system health; low voltage can cause VP44 communication loss.
  2. Inspect the ECM-to-VP44 wiring harness and connectors for corrosion, bent pins, moisture, or chafing; repair as needed.
  3. Check VP44 power and ground circuits at the pump connector for correct voltage and clean grounds.
  4. Confirm the ECM can communicate with other modules; if the ECM is unresponsive, suspect an ECM fault.
  5. If power, ground, and wiring test good and communication is still absent, the VP44 pump-mounted controller or the ECM is suspect.

Specs and test values

CheckNormal readingWhen to measureSource
Lift pump pressure at key-onAt least 10 psi (10–12 psi on a stock pump)Key on engine off, during the ~25-second primeDiesel Power Products
Lift pump pressure under loadBelow 5 psi is a red flag for the VP44Accelerating or towing, gauge on the feed lineDiesel Power Products
Battery and charging voltage12.6–12.7 V at rest when fully charged; about 13.5 V runningEngine off, then running with loads onDieselHub

Common mistake to avoid

Replacing the VP44 without testing the lift pump first. A weak lift pump starves the VP44 of the fuel it uses for cooling, so a new pump installed on a bad supply side can fail again quickly. Put a gauge on the feed line and check pressure at key-on and under load before buying the pump. Source: Diesel Power Products — checking lift pump pressure on a 24-valve Cummins.

Parts and tools you may need

Tools you’ll need

Rough cost and difficulty

Likely repairPartsShop laborWho usually does it
Wiring or connector repair$10–$1001–4 hrsDIY with tools and a manual
Battery or charging-system repair$150–$5000.5–2 hrsEasy DIY
Engine wiring harness section$100–$5002–5 hrsShop
VP44 injection pump$800–$1,6003–5 hrsShop

Typical US independent-shop figures; labor runs about $120–$180 per hour (dealers charge more). Confirm the diagnosis before buying parts.

When to see a pro

If the vehicle is no-start or stalls intermittently, have a diesel technician with Cummins/Dodge experience perform a full scan of all modules, load-test the battery/charging system, and verify VP44 supply pressure and wiring before replacing the pump or ECM. Do not attempt high-pressure fuel system service without proper training and safety equipment.

Check for recalls

Recalls are tied to your truck’s VIN, so check yours directly: enter the VIN at NHTSA’s recall lookup. Open safety recalls are repaired free at a dealer.

Sources

  1. Curated DTC seed — 5.9 Cummins 24-Valve (VP44) (curated) ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎