P1908

Pressure Control Solenoid "C" Short Circuit

Powertrain Transmission Control Solenoid Short Circuit 🟡 Moderate — Fix within a week ⚠️ Drive with Care
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What This Actually Means

In plain language — no jargon

The pressure control solenoid C has an electrical short circuit, meaning the wiring or solenoid coil is allowing current to flow where it shouldn't. Think of it like a water valve with a broken electrical switch that's stuck in the wrong position.

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Symptoms You May Notice

3 known symptoms for this code
Check Engine Light illuminated
Harsh or delayed transmission shifts
Transmission slipping or reduced power delivery
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECM monitors the resistance and current draw of the pressure control solenoid C circuit. It expects a specific voltage and resistance pattern when the solenoid is commanded on and off. A short circuit causes abnormally low resistance and excessive current draw, triggering the fault code.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Solenoid Resistance 5-15 ohms (coil dependent) Less than 2 ohms or zero ohms
Circuit Current Draw 0.5-2.0 amps Greater than 3 amps or shorted to ground
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Wiring harness connector
Inspect and reseat the solenoid connector; clean corroded pins with electrical contact cleaner.
2
Transmission fluid and filter
Change fluid and filter to remove any metallic debris from solenoid failure.
3
Pressure control solenoid C
Replace the faulty solenoid if resistance reads zero or connector cleaning does not resolve the code.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code P1908 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.

Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.
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How to Clear Code P1908

What happens after you fix the fault

Once the fault is repaired, P1908 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.

The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.

✅ Safe to Clear When
  • Fault has been diagnosed and repaired
  • You want to confirm the repair worked
  • Code appeared after a sensor was cleaned
⚠️ Do Not Clear When
  • Preparing for an emissions/PUC test
  • Root cause is still undiagnosed
  • Check engine light is flashing
Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.