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DTC codes / Jaguar codes / P1230

P1230 · JaguarFuel Pump Relay

P1230 on a Jaguar indicates that the engine control module (ECM) has detected a fault in the fuel pump relay control circuit, meaning the relay did not respond as expected when commanded. The ECM monitors the relay's control wire for expected voltage changes and sets this code when the circuit remains open, shorted, or the relay coil fails to actuate.

SystemPowertrain
Code typeJaguar specific
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering (injector circuits)

Symptoms you may notice

  • Engine cranks but does not start, or starts then stalls immediately
  • Intermittent no-start condition, especially when the engine is hot
  • Rough running or hesitation under load if the relay contacts are failing
  • Audible click from the relay area may be missing when the key is turned on
  • Often no symptoms besides the warning light if the fault is intermittent

Common causes, most likely first

  1. Failed fuel pump relay (coil open circuit or burned contacts)
  2. Corroded or loose terminals at the relay socket or fuse box
  3. Damaged wiring between the ECM and the relay control circuit
  4. Blown fuse protecting the relay coil circuit
  5. Faulty ECM driver for the relay control circuit (rare)
  6. Aftermarket alarm or immobiliser spliced into the fuel pump circuit

How to diagnose and fix it

  1. Check the fuse for the fuel pump relay circuit and replace if blown
  2. Inspect the relay socket and terminals for corrosion or looseness; clean or repair as needed
  3. Swap the fuel pump relay with an identical known-good relay and clear the code to see if it returns
  4. Test the relay coil resistance and contact continuity with a multimeter
  5. Check for voltage at the relay control wire from the ECM when the key is turned on
  6. Inspect the wiring harness between the ECM and relay for chafing or breaks
  7. If all external circuits test good, diagnose the ECM driver circuit or replace the ECM as a last resort

Relay faults that mimic pump failure

  • A failed fuel pump relay can produce the same no-start symptom as a dead fuel pump, so always test the relay before condemning the pump.
  • The relay coil can test good with a multimeter but still fail under load due to pitted contacts that only show up when current flows.
  • Corrosion inside the relay socket is a common cause on older Jaguars, especially if the fuse box has been exposed to moisture.
  • An aftermarket alarm or immobiliser that interrupts the fuel pump circuit can set P1230 even when the factory relay is fine.
  • Intermittent P1230 codes often appear only when the relay is hot, so testing should include a heat soak or wiggle test of the relay and wiring.

Can I keep driving with P1230?

If the engine starts and runs normally, you can drive to a repair shop, but avoid long trips or high-load driving because the fault may cause a sudden stall. If the engine will not start or stalls repeatedly, do not drive and have the vehicle towed.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Jaguar vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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