P1860

TCC PWM Solenoid Circuit Electrical

Car Fault Codes Chevrolet Transmission

Can you still drive? With care, short trips only

Who can fix it? Needs a workshop

Typical repair time 1 hour – 4 hours

Typical cost SAR 100 to 1,500

What it means

This is a Chevrolet (GM) manufacturer-specific code, and the same number can mean something different on other makes. The computer detected an electrical fault, such as an open or short, in the circuit of the solenoid that controls torque converter clutch (TCC) lockup inside the transmission. Lockup usually stops, so engine rpm is higher at highway speed and fuel use rises.

Models covered: Chevrolet (GM) models with the 4L60-E/4L80-E automatic, mainly 1990s–2000s.

Symptoms4

Higher than usual engine rpm at steady highway speed.
Higher fuel consumption.
Transmission fluid running hotter on long drives.
Check engine light on, usually with no obvious shifting problem.

Possible causes5

Fluid leaking into or corrosion in the transmission case connector where wiring passes into the case.
A damaged internal transmission wiring harness.
A failed TCC PWM solenoid coil.
An open or short in the wiring between the transmission and the computer.
A fault in the engine or transmission computer (rare).

How to diagnose5

Read the codes and note other solenoid codes that would point to a shared internal harness problem.
Inspect the case connector for fluid inside it or corrosion.
Measure the solenoid circuit resistance at the connector and compare with the manufacturer specification.
Use the scan tool to command the solenoid and watch the circuit status.
If readings are wrong at the connector, remove the pan and inspect the internal harness and solenoid.

How to fix5

Clean the connector and replace its seal if fluid is getting in.
Repair damaged external wiring.
Replace the internal harness if it is damaged.
Replace the TCC PWM solenoid along with a fluid and filter change.
Clear the codes, drive on the highway and confirm lockup occurs and the code does not return.

Repair cost

0–500

500–2,000

2,000–5,000

5,000+

In Saudi riyals; the highlighted part is the expected range for this fault.

Cleaning the connector or fixing an external wire is the low end, while removing the pan to replace the solenoid or harness with fresh fluid is the high end.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions

Will the transmission be damaged if I leave it?

Not right away, but without lockup the fluid runs hotter over time, and heat is a leading cause of transmission failure. Fix it soon, especially for long trips.

Why is fluid inside the case connector mentioned?

The connector seal can weaken and let transmission fluid reach the terminals, disturbing the signal. This is a known cause on these transmissions.

What is the generic equivalent?

Newer models usually use the generic code P0740 or P0743 for the TCC solenoid circuit.

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This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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