3.0L EEC-IV SYMPTOM DIAGNOSTIC

Symptom

Go To: Circuit Test (Step No.)

Engine Runs Rough Or Misses, Lack Of Power, Idle Erratic, RPM Surges, Hesitation ⁽¹⁾

S (2)

Stalls In Self-Test, Engine Stalls

S (1)

Stall During Parking Maneuvers

FF (3)

A/C Does Not Cut Off Under WOT Condition

X (52)

A/C Not Functioning

X (50)

Low Idle With A/C On

FA (11)

Stumble After Hot Restart

H (20)

Fuel Pump Runs With Engine Off

X (14)

Gasoline Fumes Under Hood

KD (1)

Black Exhaust Smoke

H (29)

Spark Knock

3.0L PFI

DG (1)

3.0L SHO

KP (1)

No Engine Cooling Fan

X (40)

Low Speed Cooling Fan Does Not Operate High Speed Cooling Fan Does Not Operate Low Or High Speed Cooling Fan Does Not Operate ⁽²⁾

X (19)

Low Or High Speed Cooling Fan Always On

X (35)

"CHECK ENGINE" Or "SERVICE ENGINE SOON" Light Always On

ML (1)

"CHECK ENGINE" Or "SERVICE ENGINE SOON" Light Never On

ML (5)

"CHECK ENGINE" Or "SERVICE ENGINE SOON" Light On Intermittently

ML (10)

"CHECK ENGINE" Or "SERVICE ENGINE SOON" Light Flashing With Erratic Idle

ML (15)

Lack Of Power At Wide Open Throttle ⁽³⁾

KT (6)

⁽¹⁾	On SHO models, verify that MAF Sensor is properly connected.

⁽²⁾	Except SHO models.

⁽³⁾	SHO models only.

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

3.0L Symptom-To-Diagnostic Flow Chart Menu

Use the Manual With the Right Hardware

When to See a Mechanic

Rather have a pro handle this?