P0738 Code: TCM Engine Speed Output Circuit (P0738)
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¿Qué significa esto?
Code P0738 indicates a problem with the TCM engine speed output circuit.
Diagnostic system: Transmission control and shift monitoring
On a Ford Focus, the P0738 code should be diagnosed as part of the transmission control and shift monitoring group. Related codes and live data from this same system can change the repair priority, so avoid replacing parts from the code name alone.
Most Common Causes for Ford Focus
- Fallo interno del PCM/ECM
- Arnés de cableado dañado o roto
- Conector eléctrico corroído o suelto
Síntomas a tener en cuenta
- La luz de Check Engine está encendida
- Cambio de marcha brusco o duro
- La transmisión patina entre marchas
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- Check fluid level and condition when the vehicle design allows it.
- Scan transmission module data, not only generic engine codes.
- Look for speed sensor, solenoid, and electrical codes before assuming internal transmission failure.
- Check for blown fuses, weak battery voltage, and damaged connectors before buying major parts.
Cómo Diagnosticar
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Assuming the transmission needs rebuilding before checking fluid, sensors, solenoids, wiring, and control-module codes. Always confirm the fault with freeze-frame data, live data, visual inspection, and circuit checks before spending money on parts.
CodePage.faq
Can I drive with the P0738 code?
If the check engine light is solid, you can usually drive to a safe location or mechanic. If the light is flashing, pull over immediately to prevent catastrophic engine or catalytic converter damage.
Will the P0738 code clear itself?
Once the underlying problem is fixed, the engine computer will run its self-checks. If it passes over several drive cycles, the light will turn off automatically. You can also clear it immediately using an OBD2 scanner.
Will this code fail an emissions test?
Yes. If the Check Engine Light is on due to the P0738 code, your Ford will automatically fail an OBD2 plug-in emissions or smog test.
What should I check first for P0738?
Check fluid level and condition when the vehicle design allows it. Scan transmission module data, not only generic engine codes. Look for speed sensor, solenoid, and electrical codes before assuming internal transmission failure.
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Estimación de reparación
Fuse, connector, wiring, cleaning, or basic inspection
Internal transmission repair or module programming after electrical checks
Incluye repuestos y mano de obra. Puede variar por ubicación.
Electrical repairs may be moderate; internal transmission repairs can be expensive and need professional confirmation.
Dificultad de reparación (DIY)
Can usually be performed at home with basic hand tools.