P2DE9
Low Severity (Level 2)Cold Start Engine Coolant Pump Underspeed
P2DE9 usually means cold Start Engine Coolant Pump Underspeed.
Can you still drive with P2DE9?
⚠️Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
Typical repair cost: $40 – $300
Severity Level 2 — Low
This code indicates a minor issue that is unlikely to cause immediate driveability problems. You can typically continue driving but should have the vehicle inspected at your earliest convenience.
Common Symptoms
- Warning light or malfunction indicator related to the engine coolant temperature sensor is illuminated
- The engine coolant temperature sensor is not operating as designed
- Diagnostic trouble code (DTC) stored in module memory
- Fault may be intermittent — code may clear itself and reappear
- Reduced vehicle functionality related to the engine coolant temperature sensor
Possible Causes
- Faulty coolant temperature sensor — most common cause, test before replacing
- Damaged or corroded wiring/connector in the engine coolant temperature sensor circuit
- Blown fuse or faulty relay for the engine coolant temperature sensor
- Poor ground connection — check and clean all related ground points
- Control module fault — rare but possible, only consider after ruling out simpler causes
Common Fixes
- Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($29-130 at shop, free at auto parts store for basic scan)
- Visually inspect the engine coolant temperature sensor wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $134 diagnostic fee at shop)
- Replace coolant temperature sensor if testing confirms it has failed — use OEM quality, avoid the cheapest no-name aftermarket parts that fail in a year ($40-250)
- Check and replace any blown fuses in the engine coolant temperature sensor fuse circuit — if fuse blows again, there's still a short that needs to be found ($2-16 for fuses)
- Perform a wiggle test on the engine coolant temperature sensor wiring harness while monitoring live data — see if the fault returns when you move the harness at different points ($0-137 diagnostic labor)
Estimated Repair Cost
These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.
Frequently Asked Questions
What does P2DE9 mean?
P2DE9 stands for "Cold Start Engine Coolant Pump Underspeed". P2DE9 usually means cold Start Engine Coolant Pump Underspeed.
Can you drive with P2DE9?
Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
How much does it cost to fix P2DE9?
Repair costs for P2DE9 typically range from $40 to $300, depending on your vehicle make, model, and local labor rates. Common fixes include: Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($29-130 at shop, free at auto parts store for basic scan); Visually inspect the engine coolant temperature sensor wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $134 diagnostic fee at shop); Replace coolant temperature sensor if testing confirms it has failed — use OEM quality, avoid the cheapest no-name aftermarket parts that fail in a year ($40-250).
Will P2DE9 clear itself?
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