Code
P1831
OLDSMOBILE
P — Powertrain
PC Solenoid Power Circuit Low Voltage
AI status
Completed
Completed
100%
Causes
- Low battery or poor battery charge
- Blown fuse or faulty relay in the solenoid power feed
- Corroded, damaged or disconnected connector at the PC solenoid
- High resistance in power or ground circuit (corrosion, damaged wires, chafing)
- Short to ground or short to voltage in harness
- Failed PC (pressure control) solenoid coil
Symptoms
- MIL (check engine) lamp illuminated
- Harsh, delayed, or erratic shifting
- Transmission may enter limp/safe mode or default shift strategy
- Reduced engine/transmission performance
- Diagnostic trouble codes stored for transmission solenoids or vehicle voltage
What to check
- Retrieve stored codes and freeze-frame data with a scan tool; note MIL conditions and related codes
- Verify battery voltage and charging system (battery at rest and while cranking)
- Inspect fuses and relays for the transmission solenoid power circuit
- Visually inspect PC solenoid connector and wiring for corrosion, damage, or pin push-out
- Backprobe the PC solenoid connector to check for power feed and control signal while key ON and while commanding solenoid with a scan tool
- Measure PC solenoid coil resistance (compare to specification)
Signal parameters
- Power feed (key ON): ~11–14 V (battery voltage) present at the solenoid power pin
- Control output: driver typically switches to ground or uses PWM; expected control pin near 0 V when commanded ON (varies by design)
- PC solenoid coil resistance (typical range): about 10–50 ohms depending on model — check vehicle spec
- PWM control frequency (if used): often tens to a few hundred Hz — refer to service manual
- Open-circuit: OL or very high resistance; Short-to-ground: near 0 V at solenoid feed without command
Diagnostic algorithm
- Use a scan tool: record P1831 plus any related codes; attempt active command of PC solenoid and watch live data/voltage and transmission pressure responses.
- Verify battery voltage ≥12.0 V (engine off) and charging system while engine runs; charge or replace battery if low.
- Inspect fuses/relays in power distribution for the transmission solenoid circuit; replace any blown fuses or suspect relays.
- Visually inspect the transmission harness, connector, and pins at the PC solenoid for corrosion, bent pins, or water intrusion; repair or replace connector as needed.
- Backprobe the solenoid connector: with key ON measure power feed and control pin. Power feed should be battery voltage; if missing, trace back to fuse/relay/connector.
- Command the solenoid ON with a scan tool while measuring the control pin. If the control pin does not change or is stuck low/high, suspect wiring or module output.
- Disconnect solenoid and measure coil resistance with DMM; compare to specification. An open or shorted coil requires solenoid replacement.
- Perform continuity and short-to-ground/power tests between solenoid connector and TCM/PCM pins. Repair wiring faults (splice, replace harness) as needed.
- If wiring and solenoid check good but control driver does not operate correctly, test or replace the TCM/PCM per OEM procedures.
- Clear codes and road test to verify repair; monitor for reoccurrence.
Likely causes
- Blown fuse or bad power feed to the transmission solenoid circuit
- Loose/corroded connector or poor ground at the transmission harness
- Open or shorted wiring to the PC solenoid (localized damage or chafe)
- Internal failure of the PC solenoid coil
- Faulty TCM/PCM driver (less common)
Fault status
Status
P1831 — PC Solenoid Power Circuit Low Voltage: low or abnormal voltage detected on the transmission pressure control solenoid power circuit; possible wiring, fuse/connector, solenoid, or control module fault.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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