What Does P1451 Mean?
The PCM is detecting abnormally low voltage on the control circuit for the EVAP switching solenoid. This indicates a short to ground, internal solenoid short, or driver circuit problem in the control module.
Common Causes
40%
Wiring harness shorted to ground due to chafing or pinched wire
30%
Internal short in switching solenoid coil to ground
20%
Water intrusion or corrosion in connector causing short circuit
10%
Failed PCM driver circuit for solenoid control
Diagnostic Steps
1
Step 1: Disconnect switching solenoid connector and check if code clears to isolate solenoid vs wiring
2
Step 2: Measure resistance between solenoid control wire and ground with solenoid disconnected (should be infinite)
3
Step 3: Inspect wiring harness routing for damage, especially near sharp edges or heat sources
4
Step 4: Check solenoid resistance and compare to specifications (typically 20-50 ohms)
5
Step 5: Test PCM driver circuit output voltage if all wiring and solenoid test normal
Estimated Repair Cost
$100 - $550
Parts + labor, varies by vehicle and location
The PCM is detecting abnormally low voltage on the control circuit for the EVAP switching solenoid. This indicates a short to ground, internal solenoid short, or driver circuit problem in the control module.
The most common cause of P1451 (Diagnostic Module Tank Leakage (DM-TL) Switching Solenoid Control Circuit Signal Low) is: Wiring harness shorted to ground due to chafing or pinched wire
Typical repair costs for P1451 range from $100 to $550, depending on the vehicle, location, and whether you do it yourself or go to a shop.
No safety concerns for vehicle operation. Only affects emissions system self-diagnostics.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1451 to identify the root cause.
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Quick Info
Category
Powertrain
System
Evaporative Emissions System
Difficulty
Type
Manufacturer
Recommended Tools
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