P2780

Downshift Switch Circuit Low

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$17–89 (est.)

Symptoms

Incorrect gear shifting
Car won't downshift
Check Engine light comes on
The car goes into emergency gearbox mode
Deterioration of vehicle dynamics

Causes

Open or short circuit in downshift circuit
Downshift switch malfunction
Problems with the wiring harness or connectors
Transmission control module (TCM) malfunction
Corrosion of contacts in an electrical circuit

How to Fix

Check the integrity of the wiring and connectors in the switching circuit
Test the downshift switch
Check the resistance of the switching circuit
Scan TCM memory for other errors
If necessary, replace the switch or repair the wiring

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