Fuel Supply Heater Control Circuit/Open
The P2687 code indicates that the Powertrain Control Module (PCM) has detected an open or malfunction in the control circuit of the fuel supply heater. This heater is used in diesel engines to warm the fuel in cold conditions, preventing gelling. An open circuit means there is a break in the electrical path, which can be caused by a faulty heater element, damaged wiring, or a defective relay or fuse.
01. Most Common Causes
- Open or shorted fuel heater element
- Damaged wiring or connectors in the heater circuit
- Blown fuse or faulty relay
- Faulty PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Hard starting in cold weather
- Engine may run rough or stall when cold
- Fuel may gel in extreme cold
03. Step-by-Step Diagnosis
Step 1: Scan for codes and note freeze frame data.
Step 2: Visually inspect the fuel heater connector and wiring for damage.
Step 3: Test the fuel heater resistance with a multimeter (specs vary, typically 0.5-2 ohms).
Step 4: Check for power and ground at the heater connector with the ignition on.
Step 5: Inspect and test the fuel heater relay and fuse.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive in cold weather as the fuel may gel, causing engine stalling or no-start. In warm weather, driving is possible but the check engine light will remain on.
How much does it cost to fix?▼
The cost typically ranges from $150 to $400, including parts and labor. The fuel heater element itself costs $50-$150, and labor adds $100-$250 depending on accessibility.