P2147

Code

LAND ROVER P — Powertrain

supply voltage of group A of the injector - low circuit

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 24 EN: 47 RU: 30

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Page language: EN

Causes

Low battery or poor battery charging (low system voltage)
Blown or corroded fuse supplying injector group
Faulty injector supply relay or relay control circuit
Damaged, corroded or poor connector at injector supply rail or harness
Short to ground or high-resistance connection in the injector supply wire
Faulty engine ground(s) or high-resistance ground connection

Symptoms

Check Engine Light (MIL) illuminated
Rough idle, hesitation or misfire(s)
Reduced engine performance or limp-home mode
Hard starting or crank/no-start in severe cases
Poor fuel economy; occasional surging under load

What to check

Read and record freeze-frame and live data with a scan tool; confirm P2147 and any related codes
Check battery voltage (key ON, engine OFF and with engine running) and charging system
Inspect fuses and relays related to injector supply/powertrain; check fuse continuity
Visually inspect injector harnesses, connectors and pins for corrosion, damage or water ingress
Backprobe and measure injector supply voltage at group connector with key ON and during cranking
Perform voltage drop tests on supply and ground circuits for injectors

Signal parameters

Expected injector supply voltage: approximately battery voltage (~11–15 V depending on charge state)
Fault threshold: supply significantly below battery voltage (commonly < ~9–10 V) will trigger fault
Injector coil resistance: varies by vehicle (refer to service manual); typical gasoline injectors are in low- to high-impedance ranges — check OEM spec
Injector control signal: ECM switches injectors to ground; supply should remain steady while pulse signals vary between ~0–battery voltage

Diagnostic algorithm

Use a scan tool: read P2147 and any associated codes; note freeze-frame and operating conditions when fault set.
Verify vehicle battery and charging system are healthy (battery state, charging voltage at idle ~13.5–14.5 V).
Inspect harness/connectors at the injector supply rail and ECM for damage, corrosion or loose terminals; repair as needed.
With key ON (engine OFF) backprobe the injector group supply pin(s) and confirm supply voltage equals battery voltage. If low, trace supply back to fuse/relay/battery.
Check continuity from the injector supply pin to the battery/fuse/relay and perform voltage-drop tests on the positive supply and ground with engine cranking.
Inspect and test related fuse(s) and the injector power/ECM relay; replace if faulty and re-check voltage.
If supply and fuses/relays are good, test for short to ground or high resistance in the supply circuit (disconnect injector group and re-test).
If wiring and external components are good, check ECM power output pins per service manual; compare to known-good values and consider ECM or power module replacement only after excluding harness and supply components.
After repairs, clear codes and perform a test drive to verify the fault does not return.

Likely causes

Corroded/damaged connector or wiring to the injector supply rail
Blown fuse or failed injector supply relay
Low battery/poor charging causing supply below threshold
Loose or high-resistance engine/chassis ground
ECM or power distribution module fault (less common)

Fault status

⚠️ Status

P2147 — Injector group A supply voltage low. Fault stored in ECM; MIL on. Check supply, fuses/relays, wiring and grounds before replacing ECM.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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P2147 — supply voltage of group A of the injector - low circuit