How do you reset the PCM on a Jeep Wrangler?
TJ Enthusiast
- Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds to discharge the PCM capacitors, which maintain the Adaptive Memory.
- Reconnect the Battery Cable.
- Turn Ignition Switch to the “On” position but DO NOT start the engine.
- Turn Headlight On.
- Turn Headlights Off.
Are there engine codes for the Jeep Wrangler YJ?
Jeep check engine codes for the Jeep Wrangler YJ and the XJ Cherokee. These codes and video may work with other OBD1 Jeeps. When Chrysler / Jeep came up with this idea for getting the engine codes, it was a very smart move. This generation of Wranglers and Cherokees had the most simple diagnostics of any other.
What is 5V output on Jeep Wrangler?
The 5v output is power for these: TPS, MAP, speed, crank & cam sensors. A sure sign you have lost that output is when you turn the key to the on position & the gauges do not move. You also lose communication with the OBDII data port & a scanner will not “communicate” & not read.
What causes a check engine light on a Jeep YJ?
12*: Battery or computer recently disconnected within the last 50 start cycles). This is a very common code. Will not trigger a “Check engine light”. 13**: No change in Manifold Absolute Pressure sensor (MAP) from start to run. 14**: MAP sensor voltage too high or too low. 15**: No speed sensor signal detected. 17*: Engine stays cold too long.
Why is my PCM not working on my Jeep Wrangler?
You also lose communication with the OBDII data port & a scanner will not “communicate” & not read. The cause may be a failed PCM but also possible that one of the sensors or its wiring is shorted to ground.
Jeep check engine codes for the Jeep Wrangler YJ and the XJ Cherokee. These codes and video may work with other OBD1 Jeeps. When Chrysler / Jeep came up with this idea for getting the engine codes, it was a very smart move. This generation of Wranglers and Cherokees had the most simple diagnostics of any other.
How can I repair my PCM on my Jeep Wrangler?
The small cover will come right off, the larger one will have to be gently pried off as it is actually the 5 volt regulator board of the PCM. This is the focus of our attention. turn it over and carefully clean any of the jelly potting compound from the solder pads of the connector strip that plugged into the other part of the unit.
12*: Battery or computer recently disconnected within the last 50 start cycles). This is a very common code. Will not trigger a “Check engine light”. 13**: No change in Manifold Absolute Pressure sensor (MAP) from start to run. 14**: MAP sensor voltage too high or too low. 15**: No speed sensor signal detected. 17*: Engine stays cold too long.
The 5v output is power for these: TPS, MAP, speed, crank & cam sensors. A sure sign you have lost that output is when you turn the key to the on position & the gauges do not move. You also lose communication with the OBDII data port & a scanner will not “communicate” & not read.