What Does P261D Mean?
The powertrain control module (PCM) has detected an abnormally high voltage in the control circuit for the secondary electric coolant pump (Pump B). This indicates a short to voltage or an internal fault in the pump control system.
Common Causes
35%
Shorted wiring or connector corrosion in coolant pump circuit causing high voltage
30%
Failed electric coolant pump with internal short to power
20%
Faulty PCM or coolant pump control module with failed driver circuit
15%
Short to battery voltage in control relay circuit
Diagnostic Steps
1
Step 1: Disconnect coolant pump B connector and check for voltage at the control wire with key on - should read 0V
2
Step 2: Inspect wiring harness for chafing, pinched wires, or damage causing short to power
3
Step 3: Check coolant pump relay operation and measure resistance across pump terminals (typically 1-5 ohms)
4
Step 4: Test PCM output circuit with oscilloscope for proper PWM signal when pump commanded on
5
Step 5: If all wiring and pump test normal, suspect failed PCM driver circuit
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The powertrain control module (PCM) has detected an abnormally high voltage in the control circuit for the secondary electric coolant pump (Pump B). This indicates a short to voltage or an internal fault in the pump control system.
The most common cause of P261D (Coolant Pump "B" Control Circuit High) is: Shorted wiring or connector corrosion in coolant pump circuit causing high voltage
Typical repair costs for P261D range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Engine may overheat if auxiliary coolant pump fails to operate properly, particularly in hybrid/turbocharged applications. Monitor coolant temperature gauge closely.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P261D to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Cooling System
Difficulty
Type
Generic (SAE)
Recommended Tools
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