Coolant Pump Control Circuit Range/Performance
The P261B code indicates that the engine control module (ECM) has detected a malfunction in the control circuit of the electric coolant pump. This pump is responsible for circulating coolant through the engine and heater core, especially during low-speed or idle conditions. The ECM monitors the pump's electrical feedback and compares it to expected values. A range/performance issue means the pump is not operating within its normal parameters, which can lead to inadequate cooling, overheating, and reduced heater performance.
1. Most Common Causes
- Faulty electric coolant pump
- Open or shorted wiring in the pump control circuit
- Poor electrical connection at the pump connector
- Failed ECM (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine overheating, especially in traffic or at idle
- Weak or no heat from cabin heater
- Coolant leaks near the pump area
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and record freeze frame data.
Step 2: Visually inspect the coolant pump and wiring for damage, corrosion, or loose connections.
Step 3: Test the pump's power and ground circuits using a multimeter (should see battery voltage with key on).
Step 4: Check the pump's resistance (typically 0.5-2 ohms) and compare to specs.
Step 5: If wiring is good, command the pump on with a scan tool and verify operation; if no response, replace the pump.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The coolant pump may fail completely, leading to engine overheating and potential damage. If the engine temperature rises above normal, stop driving immediately.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and replacement of the coolant pump, depending on labor rates and parts. Some vehicles may require additional labor for access.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.