P1282

Code

JEEP P — Powertrain

Fuel Pump Relay Control Circuit Open Or Shorted

Brand: JEEP

Type: P — Powertrain

Views: UK: 57 EN: 79 RU: 55

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Page language: EN

Causes

Open or damaged wiring between ECM and fuel pump relay/control connector
Short to battery voltage or short to ground in the relay control circuit
Corroded, bent or pushed-out relay socket pins or connector terminals
Failed fuel pump relay (stuck open/coil open/shorted)
Blown or loose fuse, fusible link, or fuel pump power feed issue
Poor or missing ground at relay or ECM

Symptoms

Malfunction Indicator Lamp (MIL) or Service Engine light illuminated
No fuel pump prime when key is turned to ON (no audible prime)
Engine crank/no start or hard start
Intermittent stalling or loss of power while driving
Blown fuse for fuel pump circuit
Fuel pressure low or no fuel pressure at rail

What to check

Scan for stored codes and freeze-frame data; note ignition key position and battery voltage at time of fault
Visually inspect fuel pump relay, fuse, relay socket, wiring harness and connectors for corrosion, damage or water intrusion
Listen for fuel pump prime with key ON; check fuel pressure with a gauge
Using a scan tool, command fuel pump ON and observe fuel pump control status/PID
Backprobe relay control terminal and measure voltage while commanding pump ON/OFF
Check fuse(s) related to fuel pump and power feed circuits for continuity

Signal parameters

Fuel pump relay control is typically a low-side driver from the ECM (ECM provides ground to energize relay coil).
Expected idle/off voltage at relay control terminal (no command): ~battery voltage (~11–13.5 V) when measured to ground (relay coil supply side may also show battery voltage).
Expected commanded (ON) voltage at relay control terminal: pulled near 0 V (≤1.0 V) to ground by ECM when activating the relay.
Pulse/PWM: some systems may vary duty cycle during cranking or protection modes—consult vehicle service manual for waveform specifics.
Continuity: resistance between relay control terminal and ECM pin should be very low (typically a few ohms; large or infinite resistance indicates open).

Diagnostic algorithm

Retrieve DTCs and freeze-frame with a scan tool. Record ignition key position and battery voltage at fault. Clear codes and attempt to re-create.
Visually inspect relay, fuse(s), wiring harness, and connectors for damage, corrosion, loose pins or water. Repair obvious faults and retest.
Verify fuel pump operation: with ignition ON listen for prime and confirm fuel pressure with a gauge. If pump does not run, continue diagnostics.
Check fuse and power feed to fuel pump relay coil and relay supply pin for battery voltage with ignition ON. Replace blown fuses as needed.
Using a scan tool, command fuel pump ON. Backprobe the relay control terminal (ECM control side) and measure voltage: expected ~0 V when commanded ON, ~battery voltage when OFF. Note any abnormal readings (stuck high, stuck low, fluctuating).
If control wire shows voltage when it should be open, trace for short to battery. If it is held to ground when it should be open, trace for short to ground.
With ignition OFF, measure continuity/resistance between relay control terminal and the ECM control pin. An open/no continuity indicates a broken wire or connector fault. Low resistance when it should be open indicates short to ground.
Swap the fuel pump relay with a known-good identical relay (if available) and re-test to rule out relay coil failure.
If wiring and relay check good, inspect ECM connector pins for damage and perform bench/oscilloscope tests of the ECM driver per factory procedure. Replace ECM only after wiring/relay confirmed good and ECM driver verified faulty.
After repairs, clear codes and perform a road test or repeated activation to confirm the fault does not return.

Likely causes

Broken/disconnected wire or terminal between ECM and relay
Relay coil open or relay contacts failed
Connector corrosion or poor mating at relay or ECM
Short to battery or ground on the relay control wire

Fault status

⚠️ Status

P1282 — Fuel Pump Relay Control Circuit Open or Shorted. ECM detected abnormal voltage/continuity on the fuel pump relay control circuit (open circuit or short to battery/ground).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-3.0 hours

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P1282 — Fuel Pump Relay Control Circuit Open Or Shorted