P2687

Code

Generic P — Powertrain

Fuel Supply Heater Control Circuit/Open

Brand: Generic

Type: P — Powertrain

Views: UK: 22 EN: 66 RU: 50

AI status

Completed

ready

Completed 100%

Page language: EN

Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
DTC P2687 stored in PCM memory
Possible hard cold starts, rough idle or reduced performance on cold start (if heater required)
No current draw from heater when commanded ON
Failed emissions test related to cold-start enrichment

Scan tool: read freeze frame/related codes and confirm P2687
Visual inspection of harness, connector and heater for damage or corrosion
Check fuses and relays supplying the fuel heater circuit
Measure connector continuity and resistance of heater element (with harness disconnected)
Back-probe PCM output while commanding heater ON and check for voltage change
Verify good ground at heater and chassis ground points

PCM command: digital ON/OFF output (expect a command present when PCM requests heater operation)
Supply voltage at heater connector when commanded ON: near battery voltage (11–14V)
Supply voltage at heater connector when not commanded: ~0V or open-circuit depending on design
Heater element resistance (typical): low ohms — verify against service spec (open = infinite)
Current draw when energized: consistent with heater rating (amps) — no current indicates open circuit
Connector continuity: near 0Ω through power and ground paths when measured cold (except when intentionally open)

Retrieve trouble code(s) and freeze-frame data with a scan tool; confirm P2687 and note when code set (cold start, etc.).
Perform a visual inspection of the fuel heater wiring, connectors, and harness for corrosion, damage, or disconnected pins; repair obvious issues.
Check fuses and relays related to the fuel heater circuit; replace if blown or faulty.
With ignition OFF and harness disconnected, measure resistance of the heater element. If infinite/open, replace heater.
Reconnect harness and back-probe the heater power pin. Command the heater ON with a scan tool; measure voltage at the connector. If no voltage present, proceed to wiring/PCM checks.
Check continuity between the PCM control pin and heater connector pin. Repair any open wiring found (splice, replace harness section).
Verify ground integrity for the heater circuit; measure voltage drop while heater command is active. Repair poor ground connections.
If wiring and ground are good but PCM does not output command voltage, test PCM driver circuit per manufacturer procedures or substitute a known-good PCM if applicable.
After repairs, clear codes and perform a road/cold-start test to confirm the heater operates and P2687 does not return.
If intermittent, perform wiggle/stress tests and re-check. Consult wiring diagrams and pinouts before replacing major components.