ECM TROUBLE CODES ⁽⁷⁾

Code

Component/Circuit Affected

EO12 ⁽¹⁾

No Distributor Signal

EO13 ⁽²⁾

Oxygen Sensor Not Ready

EO13 ⁽²⁾

(AIR, CL & Canister Purge)

EO14 ⁽²⁾⁽⁶⁾

Shorted Coolant Sensor Ckt (AIR)

EO15 ⁽²⁾⁽⁶⁾

Open Coolant Sensor Ckt (AIR)

EO16 ⁽¹⁾⁽⁵⁾

Generator Voltage Too High

EO16 ⁽¹⁾⁽⁵⁾

(All Solenoids)

EO18 ⁽²⁾

Open Crank Signal Circuit

EO19 ⁽²⁾

Shorted Fuel Pump Circuit

EO20 ⁽¹⁾

Open Fuel Pump Circuit

EO21 ⁽²⁾

Shorted TPS Circuit

EO22 ⁽²⁾

Open TPS Circuit

EO23 ⁽²⁾⁽⁴⁾

EST/By-Pass Circuit Problem (AIR)

EO24 ⁽²⁾⁽⁵⁾

Speed Sensor Circuit (VCC)

EO26 ⁽²⁾

Shorted Throttle Switch Circuit

EO27 ⁽²⁾

Open Throttle Switch Circuit

EO28 ⁽²⁾

Open 3rd/4th Gear Circuit

EO30 ⁽²⁾

ISC Circuit

EO31 ⁽¹⁾

Shorted MAP Sensor Circuit (AIR)

EO32 ⁽¹⁾

Open MAP Sensor Circuit (AIR)

EO34 ⁽¹⁾

MAP Signal Too High (AIR)

EO37 ⁽²⁾

Shorted MAT Sensor Circuit (AIR)

EO38 ⁽²⁾

Open MAT Sensor Circuit (AIR)

EO39 ⁽²⁾

VCC Engagement

EO40 ⁽²⁾

Open PS Pressure Switch Circuit

EO44 ⁽¹⁾

Lean Exhaust (AIR, CL & Canister Purge)

EO45 ⁽¹⁾

Rich Exhaust (AIR, CL & Canister Purge)

EO47 ⁽²⁾

BCM/ECM Data Problem

EO48 ⁽²⁾

EGR System Fault (EGR)

EO51 ⁽¹⁾⁽⁶⁾

ECM PROM Error

EO52 ⁽³⁾

ECM Memory Reset Indicator

EO53 ⁽³⁾

Distributor Signal Interrupt

EO55 ⁽³⁾

TPS Misadjusted

EO59 ⁽³⁾

VCC Temperature Sensor Circuit

⁽¹⁾	This fault turns on "SERVICE NOW" and "ENGINE CONTROL SYSTEM" light.

⁽²⁾	This fault turns on "SERVICE SOON" and "ENGINE CONTROL SYSTEM" light.

⁽³⁾	This fault does not turn on any light.

⁽⁴⁾	Causes system to operate on by-pass spark.

⁽⁵⁾	Disengages VCC for engine ignition cycle.

⁽⁶⁾	Forces cooling fans on full speed.

⁽⁷⁾	Functions within brackets are disengaged while specified fault remains current (hard).

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

ECM Trouble Code/Component Identification

Use the Manual With the Right Hardware

When to See a Mechanic