Retrieve and Diagnose your Check Engine Codes on a Jeep Wrangler YJ

Jeep Check Engine CodesOn a recent camping trip to Anza Borrego, my Jeep Wrangler’s check engine light appeared out of no where. There was no way that I would let this ruin my trip so I decided to fix the issue.

Diagnosing the issue was actually quite simple. No need for scanners, computers, or sensors. All you need is the keys to your Jeep and the ability to count.

So here is how to retrieve and diagnose your check engine codes on a Jeep Wrangler YJ.

What to do:

You need to first get your Jeep into diagnostic mode. Stick your key into the ignition and turn the key to ‘on’ then ‘off’, turn it back ‘on’ and back ‘off’, finally leaving it ‘on’ again. You will then see your check engine light flash, the flashing will represent what code you need to diagnose your problem.

Engine Codes:

11 – Ignition
12 – Battery disconnected within last 50 key starts
13 – Manifold Absolute Pressure (MAP) Sensor Vacuum
14 – Manifold Absolute Pressure (MAP) Sensor Electrical
15 – Distance sensor or circuit
17 – Engine running too cool
21 – Oxygen sensor or circuit
22 – Coolant temperature sensor or circuit
23 – MAT sensor or circuit
24 – Throttle Position Sensor (TPS) sensor or circuit
25 – Automatic Idle Speed (AIS) circuit
27 – Fuel injector control
31 – EVAP solenoid or circuit
33 – Air conditioning clutch relay
41 – Alternator field
42 – Automatic shutdown relay
44 – Battery temperature sensor
46 – Battery over voltage
47 – Battery under voltage
51 – Oxygen sensor – lean condition
52 – Oxygen sensor – rich condition
53 – Internal engine controller fault
54 – Distributor sync pickup
55 – End of Code output
62 – Emissions Maintenance Reminder (EMR) mileage vaccumulator
63 – Controller failure EEPROM write denied


As you can see in the video above, it is very simple process to diagnose the check engine codes on a Jeep Wrangler YJ.

It turned out that my issue was with the Throttle Position Sensor. I was able to pick up a replacement sensor at a nearby auto parts store and had it installed within minutes. This completely fixed my issue and I was able to enjoy my camping trip with peace of mind.


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