P1908 — Pressure Control Solenoid "C" Short Circuit

Will P1908 clear itself?

Sometimes P1908 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What is the most common cause of P1908?

The most common causes are: faulty transmission speed sensor, failed shift or pressure control solenoid, internal mechanical wear (clutches, torque converter).

What are the symptoms of P1908?

Drivers most often notice: Check Engine or transmission warning light on, shuddering at highway speed, slipping between gears, harsh or delayed shifting.

How much does it cost to fix P1908?

Transmission rebuild or replacement — $2,500–$5,500; Replace a shift solenoid — $300–$800; Valve body repair or replacement — $700–$1,500; Transmission fluid service — $150–$350. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

How do I diagnose P1908 myself?

Start with a scan: confirm P1908, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the automatic transmission control, and verify the suspect component against live data before buying parts.

When your vehicle's engine control module detects an electrical problem inside the automatic transmission, it logs a specific trouble code to help you pinpoint the issue. Code P1908 refers to a short circuit condition affecting Pressure Control Solenoid "C" — one of the electronic components responsible for managing hydraulic pressure inside the transmission. This falls under the powertrain category, meaning it involves both the engine and transmission systems working together.

The transmission control module constantly monitors the performance of its pressure control solenoids during operation. When P1908 is triggered, the module has identified that the electrical signal from Solenoid C is either absent, grounded incorrectly, or behaving outside its expected parameters. This diagnosis typically requires multiple drive cycles to confirm — a single momentary glitch will not set the code permanently. At the moment the fault occurs, the module saves a freeze frame snapshot, recording engine RPM, load percentage, coolant temperature, and vehicle speed. Technicians examine this data first because it reveals exactly what conditions existed when the problem was detected.

Understanding what P1908 means helps you make informed decisions about repair priorities. The pressure control solenoid regulates fluid pressure to specific clutch packs and gear sets. When this component malfunctions electrically, the transmission cannot properly modulate line pressure, leading to irregular shifting behavior or complete loss of gear engagement in severe cases.

Common symptoms of P1908

• Illuminated Check Engine light or transmission warning indicator on the dashboard
• Noticeable shuddering or vibration, particularly at highway cruising speeds
• Slippage between gears where the engine revs without corresponding acceleration
• Shifting that feels harsh and abrupt, or alternatively, delayed engagement when changing gears
• Complete failure to move in any gear when the problem is severe
• Transmission locked into a single gear, often third or fourth, commonly called limp mode

What causes P1908?

• Faulty or internally shorted pressure control solenoid C
• Wear or damage to the valve body where the solenoid operates
• Damaged wiring or corroded connectors within the transmission harness
• Insufficient or severely degraded transmission fluid
• Failed transmission control module in rare cases
• Electrical short to ground in the solenoid control circuit

How to diagnose P1908

1. Connect an OBD2 scanner and retrieve all stored codes — confirm P1908 is present, then record the freeze frame data. This snapshot captures engine operating conditions at the exact moment the fault was detected and guides your next steps.
2. Check for any related diagnostic trouble codes that may point to the underlying cause. Research manufacturer technical service bulletins using your vehicle's VIN through the automaker's website or nhtsa.gov — many common P1908 issues have known fixes or software updates.
3. Perform a thorough visual inspection of the wiring harness and electrical connectors leading to the transmission. Look for damaged insulation, broken wires, corrosion buildup, or loose connections that could interrupt the solenoid's electrical signal.
4. Inspect the transmission fluid level and condition. Healthy fluid appears red or pink and has no burnt odor. Dark brown or black fluid with a burnt smell indicates internal component wear that may have caused the solenoid failure.
5. Use a transmission-capable scanner to read live data: solenoid operation status, input and output speed sensor readings, and actual vs. commanded line pressure. This data confirms whether the solenoid is responding to commands.
6. Clear the P1908 code after completing your inspection, then perform a full drive cycle that replicates the conditions recorded in the freeze frame. If the code reappears, you have confirmed an active fault requiring repair.

How to fix P1908

Approach repairs from the least expensive to the most invasive. Many P1908 faults resolve without a full transmission overhaul:

• Transmission fluid service (drain, fill, and filter replacement) — $150–$350
• Replace Pressure Control Solenoid C — $300–$800
• Valve body repair or replacement — $700–$1,500
• Complete transmission rebuild or replacement — $2,500–$5,500

How much does it cost to fix P1908?

Final repair cost depends entirely on which component triggered the P1908 code. At independent shop labor rates in the United States, expect the following ranges for parts and labor combined: transmission fluid service costs between $150 and $350, solenoid replacement runs $300 to $800, valve body work ranges from $700 to $1,500, and a full transmission rebuild or replacement requires $2,500 to $5,500. Across all possible repair scenarios, fixing P1908 typically falls somewhere between $150 and $5,500. Proper diagnostic testing before purchasing parts almost always saves money — the most expensive repair is rarely where you should start.

Can you drive with P1908?

This code carries a caution severity rating. If your transmission continues to shift and the vehicle moves normally without slippage or harsh engagement, limited driving on surface streets is acceptable while you arrange diagnosis and repair. Avoid highway speeds and aggressive driving — any slip between gears or limp mode engagement significantly accelerates internal wear and can transform a $300 solenoid replacement into a $3,000 transmission rebuild. Address this code promptly to prevent minor damage from becoming major expense.