Code
P1831
CHEVROLET
P — Powertrain
PC Solenoid Power Circuit Low Voltage
Views:
UK: 29
EN: 41
RU: 35
AI status
Completed
Completed
100%
Causes
- Blown fuse or faulty relay in the solenoid power feed
- Low battery or poor charging system voltage
- Poor or corroded connector or terminal at the solenoid or harness
- Open or high-resistance wiring in the power feed circuit
- Short to ground on the power feed
- Faulty PC solenoid (internal open or short)
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Transmission may go into limp mode or default shift strategy
- Harsh, delayed, or incomplete shifts
- Inability to hold proper line pressure; slipping or loss of drive
- Possible abnormal transmission noise or reduced performance
What to check
- Read freeze frame and full scan data; note battery/charging voltage and when the code set
- Visually inspect connectors and wiring at the PC solenoid and TCM for corrosion, damage, or loose pins
- Check related fuse(s) and relay(s) for the transmission solenoid power feed
- Measure battery and charging system voltage with engine off and idling
- Backprobe the solenoid power terminal with ignition ON and while commanding the solenoid with a scan tool
- Measure coil resistance of the PC solenoid (disconnect connector first)
Signal parameters
- Expected power feed voltage: approximately battery voltage (typically ~11–14 V) at the solenoid connector with ignition ON
- Expected coil resistance: low-ohm range (typically tens of ohms) — varies by model; consult service data for exact spec
- When the TCM/ECM commands the solenoid ON, driver should either switch ground or provide switched battery depending on circuit design; no large voltage drop should occur
- Excessive voltage drop (>1 V under load) between fuse/relay and solenoid indicates high resistance in the circuit
- Typical solenoid current: moderate (hundreds of milliamps to low amps) — exact current varies by solenoid design
Diagnostic algorithm
- Retrieve codes, freeze frame, and live data. Note vehicle voltage when the fault occurred.
- Visually inspect connectors, wiring, and mounting for damage, corrosion, or loose terminals at the PC solenoid, fuse/relay box, and TCM.
- Check the fuse(s) and relay supplying the solenoid circuit; replace a blown fuse. Test or swap the relay if suspected.
- Measure battery voltage at the battery and at the solenoid power pin with ignition ON; expected ~battery voltage. If low, inspect wiring back to fuse/relay and battery.
- Command the PC solenoid ON/OFF with a capable scan tool while backprobing the power and control terminals. Observe voltage behavior and any excessive drop under command.
- With the connector disconnected, measure PC solenoid coil resistance and compare to service specification. An open or very high resistance indicates a bad solenoid.
- Check continuity from the solenoid power pin to the fuse/relay and to the TCM power/driver pin (as applicable). Repair any high-resistance or open circuits; clean and repair corroded terminals.
- If wiring and solenoid are good but low voltage persists at the driver, test the TCM/ECM driver output per factory procedure or consult service documentation. Replace or reflash module only after verifying harness and component integrity.
- Clear codes and perform a road test/functional tests. Re-scan to confirm the code does not return.
Likely causes
- Corroded/loose connector at the PC solenoid
- Blown fuse or bad relay in the solenoid power circuit
- High-resistance wiring or broken conductor between fuse/relay and solenoid
- Faulty PC solenoid coil (open or high resistance)
- Faulty TCM/ECM driver (less common)
Fault status
Status
PC solenoid power circuit low voltage — insufficient supply or open/high-resistance circuit to transmission pressure control solenoid. Check battery, fuses/relays, wiring, connector, and solenoid.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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