2000 Grand Cherokee Malfunction Indicator light

[sportsman]

The malfunction Indicator Light comes on when I am towing by Boat.
The Transmision is shifting gears constantly.
When I'm not towing, the Light goes out but the transmission still shifts gears
and has a jurking to it. Sometimes, the engine will miss.
Could this be a bad sensor in the control system?
What should I be looking for?

[Bob D.]

Get the codes from the Powertrain Control Module (PCM):
Insert the key in the ignition. Turn ignition key ON and OFF three times, on the third ON leave it in the ON position. The odometer reading will be replaced by a trouble code. Write down the numbers displayed on the odometer and post them here.

Also post the engine size. (4.0 liter six or 4.7 v8)

[sportsman]

Originally Posted by Bob D.

Get the codes from the Powertrain Control Module (PCM):
Insert the key in the ignition. Turn ignition key ON and OFF three times, on the third ON leave it in the ON position. The odometer reading will be replaced by a trouble code. Write down the numbers displayed on the odometer and post them here.

Also post the engine size. (4.0 liter six or 4.7 v8)

The numbers are:P O 203,202,201,204,205,206,207,208 & P O 121.
It has a 4.7 v8 engine.

[Bob D.]

P0201, 202, 203, 204, 205, 206, 207, and 208 are individual references to each cylinder, (from 1 to 8) all having the same fault description:

Injector Control Circuit.
An open or shorted condition detected in control circuit for the Injector or the injector bank.

P0121 is:
Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem
TPS signal does not correlate to MAP sensor signal.

This probably means a bad TPS (Throttle Position Sensor)

That may account for the misfire, and even the erratic shifting. (engine torque changes)
I've never seen a bad TPS cause problems with the fuel injectors though. Unless it's really shot.
In any case, the TPS should be replaced.

The TPS is located on the throttle body and not very expensive or difficult to change.

[sportsman]

Originally Posted by Bob D.

P0201, 202, 203, 204, 205, 206, 207, and 208 are individual references to each cylinder, (from 1 to 8) all having the same fault description:

Injector Control Circuit.
An open or shorted condition detected in control circuit for the Injector or the injector bank.

P0121 is:
Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem
TPS signal does not correlate to MAP sensor signal.

This probably means a bad TPS (Throttle Position Sensor)

That may account for the misfire, and even the erratic shifting. (engine torque changes)
I've never seen a bad TPS cause problems with the fuel injectors though. Unless it's really shot.
In any case, the TPS should be replaced.

The TPS is located on the throttle body and not very expensive or difficult to change.

THANKS FOR INFO. I WILL TRY THIS AND LET YOU KNOW IF THIS WAS THE PROBLEM.