P1838

Internal Mode Switch 'A' Circuit High Voltage

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$17–67 (est.)

Symptoms

Incorrect display of the current transmission mode on the dashboard
Gear shifting problems
Check Engine Light Illuminates
The transmission may go into emergency mode
The car may not start in some selector positions

Causes

Short circuit to power in switch circuit
Broken or damaged wiring
Switch contact corrosion
Malfunction of the internal mode switch
Transmission control module (TCM) problems

How to Fix

Check the integrity of the wiring and connectors in the switch circuit
Measure resistance and voltage at the mode switch
Check for short circuit to power
If necessary, replace the mode switch
Scan the transmission control module for additional errors

Related codes

P1839 P1840 P0705

Error P1838 by Vehicle Brand

Ford Lincoln Mercury