Failed EFE heater element (open circuit or burned out); Corroded, loose, or disconnected electrical connector at the EFE heater; Damaged or chafed wiring between the EFE heater and the PCM or relay; Blown fuse or faulty EFE heater relay; PCM internal driver circuit failure (less common); Intake manifold carbon buildup causing overheating and heater failure (indirect cause)

DTC codes / Suzuki codes / P1250

P1250 · SuzukiEFE Heater Circuit Fault

Q: What does code P1250 mean?

EFE Heater Circuit Fault. P1250 on Suzuki vehicles indicates that the Powertrain Control Module (PCM) has detected a fault in the Early Fuel Evaporation (EFE) heater circuit, which preheats the intake manifold on cold starts to improve driveability and reduce emissions. The PCM monitors the heater element's electrical current and sets this code when the circuit is open, shorted, or drawing current outside the expected range.

P1250 on Suzuki vehicles indicates that the Powertrain Control Module (PCM) has detected a fault in the Early Fuel Evaporation (EFE) heater circuit, which preheats the intake manifold on cold starts to improve driveability and reduce emissions. The PCM monitors the heater element's electrical current and sets this code when the circuit is open, shorted, or drawing current outside the expected range.

SystemPowertrain

Code typeSuzuki specific

SeverityLow

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illumination of the Check Engine Light (CEL) on the dashboard
Often no symptoms besides the warning light, especially in warm weather
Rough idle or stumbling during the first few minutes after a cold start
Hesitation or flat spots when accelerating while the engine is cold
Slightly higher fuel consumption during warm-up
In rare cases, a noticeable burning smell from the engine bay if the heater element shorts

Common causes, most likely first

Failed EFE heater element (open circuit or burned out)
Corroded, loose, or disconnected electrical connector at the EFE heater
Damaged or chafed wiring between the EFE heater and the PCM or relay
Blown fuse or faulty EFE heater relay
PCM internal driver circuit failure (less common)
Intake manifold carbon buildup causing overheating and heater failure (indirect cause)

How to diagnose and fix it

Verify the code with a scan tool and inspect freeze-frame data for coolant temperature and intake air temperature to confirm cold-start conditions.
Locate the EFE heater (often mounted on the intake manifold) and visually inspect the connector and wiring for corrosion, looseness, or damage.
Check the EFE heater fuse and relay; test the relay operation with a multimeter or by swapping with a known-good relay.
Measure the resistance of the EFE heater element with a multimeter and compare to the manufacturer's specification (typically a few ohms); an open circuit indicates a failed heater.
Backprobe the heater connector and check for battery voltage on the power side and a good ground on the control side when the engine is cold and running.
If the circuit tests good but the code persists, check the PCM driver by commanding the EFE heater on with a scan tool and monitoring current draw or voltage drop.
Replace the faulty EFE heater, repair wiring, or replace the PCM as needed, then clear the code and verify the repair with a cold-start drive cycle.

EFE Heater Circuit Fault Diagnosis Tips

A common misdiagnosis is replacing the EFE heater when the real problem is a corroded ground connection at the intake manifold, which mimics an open heater circuit.
The EFE heater only operates during cold starts, so the code may not set again until the next cold morning; always perform diagnostics when the engine is cold to observe live data.
On some Suzuki models, the EFE heater is integrated into the intake manifold gasket and a coolant leak can damage the element, so check for coolant residue around the heater.
A faulty EFE heater can cause a lean condition during warm-up that may set lean codes (P0171) or misfire codes (P0300) without ever setting P1250 if the heater fails gradually.
Do not overlook the EFE heater relay; it often fails due to stuck contacts, causing the heater to stay on continuously and overheat, which can melt the connector.

Can I keep driving with P1250?

The vehicle is safe to drive with P1250 because the EFE heater only affects cold-start emissions and driveability, but avoid heavy acceleration or towing until the engine is fully warmed up. Prolonged driving with a faulty heater may increase emissions and slightly reduce fuel economy, so schedule repairs soon.

Tools that help

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Guidance is general and written for Suzuki vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.