P0702

Transmission Control System Electrical

Car Fault Codes Transmission

Can you still drive? With care, short trips only

Who can fix it? Needs a workshop

Typical repair time 30 minutes – 5 hours

Typical cost SAR 100 to 5,000

What it means

The transmission control module (TCM) has detected an electrical fault in the control system, such as a problem with module power or ground, or in the solenoid circuits. The module usually puts the transmission in limp mode to protect it.

Symptoms4

Check engine light on, possibly with a transmission warning message.
Transmission stuck in one gear (limp mode) with clearly weak acceleration.
Harsh shifts or no shifting at all.
Other transmission electrical or system voltage codes stored.

Possible causes6

A corroded or loose transmission connector, or fluid or water inside it.
An open or short in the solenoid wiring or power supply wiring.
A blown fuse or faulty transmission power relay.
Poor ground connections, or a weak battery and low charging voltage.
An electrical fault inside a solenoid or in the internal transmission harness.
A fault in the TCM itself (less common).

How to diagnose5

Read all TCM codes; this code is often stored with another code that names the faulty circuit.
Measure battery and charging voltage and check the transmission fuses and relays.
Inspect the transmission and TCM connectors for corrosion, fluid intrusion or loose pins.
Measure power and ground at the TCM and compare with the manufacturer wiring diagram.
Measure solenoid resistance and compare it with the manufacturer specification.

How to fix6

Clean the connectors, repair loose pins and stop fluid from entering them.
Replace the faulty fuse or relay after finding why it failed.
Repair open or shorted wiring and poor grounds.
Replace the faulty solenoid or internal harness.
Replace and program the TCM only after ruling out other causes.
Clear the codes, then road test and confirm normal shifting returns.

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.

The cost is low for a connector, fuse or wiring repair, and higher when an internal harness, solenoids or a new TCM with programming is needed.

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

Can a weak battery cause this code?

Yes. Low voltage or a poor ground can make the module see a fault in the solenoid circuits, so check the battery and charging system first.

Does this code mean the TCM is bad?

Rarely. Wiring, connectors and fuses are far more common causes, and the module should only be replaced after power, ground and circuits are confirmed good.

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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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