P1250

Code

CHRYSLER P — Powertrain

Early Fuel Evaporation Heater Circuit

Brand: CHRYSLER

Type: P — Powertrain

Views: UK: 27 EN: 38 RU: 24

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Page language: EN

Causes

Blown fuse or faulty relay for the EVAP heater circuit
Open or shorted wiring between heater and PCM/power source
Corroded, loose or damaged connector at the heater or ground
Failed EVAP heater element or heater assembly
Poor ground connection
Water intrusion or contamination in connector

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Stored P1250 and possibly other EVAP-related codes
Vehicle may fail emissions readiness or emissions test
Possible fuel vapour smell near vehicle (if EVAP not operating)
EVAP system self-tests or functions may be disabled

What to check

Read and record freeze frame and related EVAP codes with a scan tool
Check vehicle Service Manual/wiring diagram for EVAP heater circuit and connector pinout
Visually inspect wiring, connectors, and ground for corrosion, damage or water
Check relevant fuses and relays for continuity and operation
Backprobe harness at heater connector; check for battery voltage (or PCM-specified control signal) and proper ground
Measure heater element resistance with connector disconnected

Signal parameters

Key ON (engine off): battery voltage should be present at the power feed to the heater circuit (if so equipped)
When PCM commands heater ON: control circuit should switch to ground or supply voltage per wiring diagram; see live data
Typical heater element resistance (varies by model): low resistance profile — commonly a few ohms to a few tens of ohms (refer to factory spec)
Expected current draw when energized: typically under a few amps (check factory spec)
Open circuit or near-infinite resistance indicates heater element open or wiring open
Very low resistance to ground or short to power indicates short circuit

Diagnostic algorithm

With an OBD-II scanner, confirm P1250 and note any related EVAP or heater codes and freeze frame data.
Review wiring diagram and locate heater, fuse, relay, and PCM connector pins for the circuit.
Visually inspect harness and connectors for damage, corrosion, bent pins, or water intrusion; repair as needed.
Check relevant fuse(s) and relay(s). Replace blown fuse or faulty relay and retest.
Disconnect heater connector. Measure resistance of heater element to ground and between power/ground terminals; compare to factory spec. Replace heater if out of spec.
With connector unplugged, check for battery voltage at the power feed (key ON) and continuity to PCM control pin. Repair open circuits.
Backprobe the control pin at the heater harness and command the heater ON with a scan tool. Verify the PCM is commanding and that voltage/current change occurs. If command present but circuit not energizing, trace wiring for open/short.
If circuit shows short to power/ground, isolate by disconnecting sections and find shorted splice or component.
After repairs, clear codes and perform drive cycle and EVAP self-tests to confirm repair. If fault returns and wiring/components verify good, consult wiring diagrams and consider PCM testing/replacement as last resort.
Check for Technical Service Bulletins (TSBs) related to EVAP heater or P1250 for the specific model and model year before replacing major components.

Likely causes

Damaged wiring or connector at the EVAP heater
Failed heater element or assembly
Blown fuse or bad relay supplying the heater
Corroded/poor ground or connector
PCM driver fault (verify after checking wiring and components)

Fault status

⚠️ Status

PCM detected abnormal condition in the Early Fuel Evaporation heater circuit (open/short/incorrect current). MIL set. Inspect EVAP heater, wiring, fuses/relays, grounds and PCM control.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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