Faulty ESO solenoid with an open or shorted internal coil; Damaged or corroded wiring harness connector at the solenoid; Broken, chafed, or shorted wire in the ESO control circuit; Poor ground connection for the solenoid or PCM; Failed PCM driver for the ESO circuit (less common); Aftermarket alarm or remote start system improperly tied into the shut-off circuit

DTC codes / Ford codes / P1170

P1170 · FordESO Engine Shut Off Solenoid Fault

Q: What does code P1170 mean?

ESO Engine Shut Off Solenoid Fault. P1170 on Ford vehicles indicates that the Engine Shut Off Solenoid (ESO) circuit has a fault, meaning the powertrain control module (PCM) detected an unexpected voltage or current condition on the solenoid's control circuit. The ESO solenoid is used on certain Ford diesel applications to cut fuel or air to stop the engine, and this code sets when the PCM's commanded state does not match the feedback it receives.

P1170 on Ford vehicles indicates that the Engine Shut Off Solenoid (ESO) circuit has a fault, meaning the powertrain control module (PCM) detected an unexpected voltage or current condition on the solenoid's control circuit. The ESO solenoid is used on certain Ford diesel applications to cut fuel or air to stop the engine, and this code sets when the PCM's commanded state does not match the feedback it receives.

SystemPowertrain

Code typeFord specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Engine may not shut off immediately when the key is turned to the off position
Hard starting or a no-start condition if the solenoid fails to open
Rough running or stalling shortly after startup on some applications
A clicking or buzzing noise from the solenoid area when the ignition is cycled

Common causes, most likely first

Faulty ESO solenoid with an open or shorted internal coil
Damaged or corroded wiring harness connector at the solenoid
Broken, chafed, or shorted wire in the ESO control circuit
Poor ground connection for the solenoid or PCM
Failed PCM driver for the ESO circuit (less common)
Aftermarket alarm or remote start system improperly tied into the shut-off circuit

How to diagnose and fix it

Verify the code with a scan tool and check for any related powertrain codes before proceeding
Inspect the ESO solenoid connector and wiring for corrosion, loose pins, or physical damage
Measure the solenoid coil resistance with a multimeter and compare to the manufacturer's specification
Check for battery voltage and ground at the solenoid connector with the key on and during commanded shut-off
Perform a wiggle test on the harness while monitoring solenoid voltage to reveal intermittent faults
If the circuit tests good, command the ESO solenoid on and off with a bidirectional scan tool to confirm PCM driver operation
Replace the ESO solenoid only after confirming the circuit and PCM are functioning correctly

ESO solenoid faults that fool good technicians

A loose or corroded ground strap between the engine and chassis can cause the PCM to see an incorrect ESO circuit voltage, mimicking a failed solenoid.
Aftermarket remote start or alarm systems spliced into the shut-off wire often introduce resistance that sets P1170 without any hard failure of the factory solenoid.
The ESO solenoid is not present on all Ford vehicles; this code only applies to models equipped with the engine shut-off solenoid, typically certain diesel applications.
A weak or failing battery can cause the PCM to misreport solenoid feedback during cranking, so always load-test the battery before condemning the solenoid.
Clearing the code and having it return immediately points to a hard circuit fault, while an intermittent code often traces to a chafed wire near the engine mount or exhaust.

Can I keep driving with P1170?

You can usually drive the vehicle to a repair shop, but be aware that the engine may not shut off promptly with the key, so avoid parking situations where a runaway engine could be dangerous. Do not continue driving if the engine fails to start or stalls repeatedly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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