ODB Code Fix: P0120

Imagine traveling down the highway to beautiful Colorado, then you feel like there is something terribly wrong with your vehicle. Suddenly, its jolting back and forth and you lose your cruise control at 80 mph. The check engine light comes on, and you are 3 hours from your destination. There are no towns or cities surrounding you .... only the dark night and wide open plains. Doesn't sound very fun does it? This is what happened recently to part of the Mojeepin.com staff. We were almost to our destination and then this happens. We had no clue what was going on with our 99 Jeep Grand Cherokee. It was just dying with no excuses. We couldnt even get the vehicle up to 60 without it tugging around and shaking when it was shifting. A scary thought.

Once we arrived at our destination in Denver, we put the Jeep to rest and went to catch some shut eye. The next morning came and we knew we had to find out what was going on. We headed over to the local Autozone and had them hook up a diagnostics tool. The ODB code it returned was a P0120. Meaning that the Throttle/Petal Position Sensor/Switch A Circuit Malfunctioned....Now to some this means nothing and others this means that we need to get this thing fixed ASAP.

Being that we just bought the Grand Cherokee, little was known about the engine and sensors that keep the thing going. All we knew was that it was up by the thottle body....We asked the guys at Autozone if they had a throttle sensor replacement and they did.

Manufactured by WELLS (msrp. $29.99), the sensor was a quick fix. We had to buy a star bit tool to aid us in the process, but all in all, it was only 2 screws and an O-ring. We unpluged the harness from the sensor and tossed the old one away. Bolted down the new sensor, plugged in the harness and tightened everything down. We used a handy Actron Pocketscan to reset the codes and turn off the check engine light, then we tested the Jeep® for any other ODB II codes. We had a clean bill of health, and we were ready to head into the mountains. We want to thank the guys out in Westminster CO for the great advice.