P2147 — Fuel Injector Group "A" Supply Voltage Circuit Low

P2147 — Fuel Injector Group "A" Supply Voltage Circuit Low. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: weak fuel pump or clogged fuel filter, vacuum or intake leaks skewing the mixture, faulty fuel pressure regulator.

powertrain (engine/transmission)

Is it safe to drive?

Drive with caution Drive with caution. Mixture and fuel-pressure faults can cause stalling, hesitation in traffic and — when severe — catalyst damage. Avoid long trips until diagnosed.

How to diagnose with an OBD scanner

  1. Read the code and freeze frame Connect an OBD2 scanner, confirm P2147 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
  3. Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the fuel delivery and mixture control for damage, corrosion, chafing or poor contact.
  4. Subsystem check Check for supply voltage at the fuel injector group "A" supply voltage connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
  5. Subsystem check Measure fuel pressure at the rail and compare with factory specification at idle and under load.
  6. Subsystem check Check short-term and long-term fuel trims in live data to see which way the mixture is off.
  7. Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2147 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P2147 (parts and labor, USD, independent shop rates): Clean or replace injectors: $200–$800; Replace the fuel filter: $80–$200; Replace the pressure regulator or sensor: $150–$450; Replace the fuel pump: $400–$900. Overall, fixing P2147 usually costs between $80 and $900. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

How much does it cost to fix P2147?

Clean or replace injectors — $200–$800; Replace the fuel filter — $80–$200; Replace the pressure regulator or sensor — $150–$450; Replace the fuel pump — $400–$900. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

What are the symptoms of P2147?

Drivers most often notice: rough idle and hesitation, fuel smell in severe cases, hard starting or long cranking, loss of power under load.

How do I diagnose P2147 myself?

Start with a scan: confirm P2147, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the fuel injector group "A" supply voltage, and verify the suspect component against live data before buying parts.

What is the most common cause of P2147?

The most common causes are: weak fuel pump or clogged fuel filter, vacuum or intake leaks skewing the mixture, faulty fuel pressure regulator.

Is it safe to drive with P2147?

Drive with caution. Mixture and fuel-pressure faults can cause stalling, hesitation in traffic and — when severe — catalyst damage. Avoid long trips until diagnosed.

What does P2147 mean?

P2147 (Fuel Injector Group "A" Supply Voltage Circuit Low) is stored when self-diagnostics detect abnormal readings or behaviour of the fuel delivery and mixture control. It belongs to the powertrain (engine/transmission) category.

“Circuit low” means the voltage on the fuel injector group "A" supply voltage circuit stays below the expected minimum — close to ground. The usual physical reasons are a short to ground, a chafed wire touching metal, a missing supply voltage, or a failed component dragging the signal down.

To set P2147, the control module compares live readings of the fuel delivery and mixture control against calibrated limits, usually over several drive cycles. Alongside the code it stores a freeze frame — a snapshot of rpm, load, coolant temperature and vehicle speed at the moment of failure. Reading that snapshot first saves diagnostic time.

What causes P2147?

  • signal wire shorted to ground (chafed insulation)
  • failed fuel injector group "A" supply voltage pulling the signal low
  • missing supply voltage to the fuel injector group "A" supply voltage
  • clogged or leaking fuel injectors
  • faulty fuel rail pressure sensor or wiring
  • weak fuel pump or clogged fuel filter
  • contaminated or incorrect fuel
  • vacuum or intake leaks skewing the mixture
  • faulty fuel pressure regulator

Common symptoms of P2147

  • rough idle and hesitation
  • fuel smell in severe cases
  • hard starting or long cranking
  • loss of power under load
  • Check Engine Light on
  • increased fuel consumption

How to diagnose P2147

  1. Connect an OBD2 scanner, confirm P2147 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
  3. Visually inspect the wiring harness and connectors related to the fuel delivery and mixture control for damage, corrosion, chafing or poor contact.
  4. Check for supply voltage at the fuel injector group "A" supply voltage connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
  5. Measure fuel pressure at the rail and compare with factory specification at idle and under load.
  6. Check short-term and long-term fuel trims in live data to see which way the mixture is off.
  7. Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2147 does not return.

How to fix P2147

Start with the cheapest and most common causes before replacing expensive parts:

  • Clean or replace injectors — $200–$800
  • Replace the fuel filter — $80–$200
  • Replace the pressure regulator or sensor — $150–$450
  • Replace the fuel pump — $400–$900

How much does it cost to fix P2147?

Repair cost depends on which component actually failed. Typical scenarios for P2147 (parts and labor, USD, independent shop rates):

  • Clean or replace injectors: $200–$800
  • Replace the fuel filter: $80–$200
  • Replace the pressure regulator or sensor: $150–$450
  • Replace the fuel pump: $400–$900

Overall, fixing P2147 usually costs between $80 and $900. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Can you drive with P2147?

Drive with caution. Mixture and fuel-pressure faults can cause stalling, hesitation in traffic and — when severe — catalyst damage. Avoid long trips until diagnosed.

Related OBD2 codes