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P1237

Injector Circuit Cylinder 6 Intermittent.

  • Saturn
  • Powertrain
  • Manufacturer code
  • Medium severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
2
AreaFuel and air metering (injector circuit)
37
FaultThe specific fault in that area

What it means

P1237 on a Saturn means the engine control module has detected an intermittent fault in the fuel injector circuit for cylinder 6. The module monitors the injector driver circuit and saw a brief open circuit, short or abnormal voltage that came and went rather than staying present. Because the fault is intermittent, the injector may work normally most of the time.

Symptoms

  • Misfire or rough running that comes and goes, mainly on cylinder 6
  • Engine hesitation or stumbling under acceleration
  • Intermittent loss of power
  • Hard or extended starting at times
  • Check engine light on, possibly flashing during a heavy misfire
  • Poorer fuel economy

Possible causes

  • Loose, corroded or damaged connector at the cylinder 6 injectorlikely
  • Chafed, stretched or broken wiring in the cylinder 6 injector harness (open circuit or short to ground or voltage)likely
  • Injector with an intermittently failing internal coil windingpossible
  • Poor terminal contact or corrosion at the engine control module connectorpossible
  • Intermittent fault in the injector supply or ignition feed to the injectors (fuse, relay or connector)possible
  • Internal fault in the injector driver of the engine control modulerare

How to diagnose

  1. Read all stored and pending codes and note the freeze frame data, including engine temperature, load and speed when the fault set
  2. Check for other injector or misfire codes to see whether the fault is isolated to cylinder 6
  3. Visually inspect the cylinder 6 injector connector and harness for damage, heat, chafing, oil contamination and corrosion
  4. With the engine running, gently wiggle the connector and harness while watching for a change in idle quality or live misfire data
  5. Measure the injector coil resistance and compare it with the specification for your engine, as values depend on the model
  6. Check the injector supply voltage and the related fuse and connectors, using the wiring diagram for your model
  7. Test the injector driver signal with a suitable meter or oscilloscope to see whether the pulse drops out
  8. Inspect the engine control module connector pins for spread terminals or corrosion, and check the circuit continuity back to the module

How to fix

  • Clean, reseat or replace the damaged injector connector and terminals
  • Repair or replace the damaged section of injector wiring using proper soldered and sealed joints
  • Replace the cylinder 6 injector if its resistance is out of specification or it fails intermittently
  • Repair terminal or supply faults found in the injector feed, such as fuse holder or connector problems
  • Repair or replace the engine control module only after wiring and injector faults have been ruled out and the driver fault is confirmed

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but fix it soon as an intermittent misfire can worsen and may damage the catalytic converter. If the warning light flashes or the engine runs badly, stop driving and have it checked.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

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