Cruise Control Causing CEL - How To Bypass

[jeewagon]

I have a 2004 Wrangler Rubicon that I recently purchased, and I'm going through it and working out the kinks. The cruise servo under the hood was removed and the vacuum port was plugged. It keeps throwing a P1595 code. The connector for the servo is just sitting under the hood not plugged into anything. I'm assuming this is why it keeps throwing a code?

I don't really care if I have cruise or not I would just like to get the CEL to turn off. Is there a way I can "bypass" or trick the computer into thinking the servo is still there? Maybe a jumper wire between two pins on the connector? I have attached pictures of the connector below. Any advice would be appreciated.

 

[jeewagon]

Bump

 

[jonny jeep]

From the FSM it seems that the code should only be set if the cruise is turned on and then the PCM doesn't see the solenoids operating.
Could you be accidently catching the button as you are driving?

You can't just disconnect the steering wheel switches as they are resistor multiplexed and the PCM senses different voltages to determine which button has been pressed. The left switch has an additional resistor so the PCM doesn't see 5V unless the switches are disconnected which would give you a different trouble code.

It might be worth unplugging the switches and measuring the resistance of the switches with no buttons pressed. If the connector on the loom side were shorted out with a resistance of that value, the PCM should think the switches are connected, but pressing any of them would have no effect. It wouldn't therefore turn the cruise on, so shouldn't check for solenoid operation, and in turn no trouble code should be generated.

That's the way it seems it should work to me.

 

[Steve04]

Are you sure this is the only fault code? Because I don’t believe that that code would turn on the cel

 

[TJ Jim]

Found this on the World Wide Web. Do your brake lights light?


The most common cause of this issue is a faulty Speed Control Brake Switch located at the brake pedal. Other possible causes include an open or shorted Speed Control Brake Switch harness, poor electrical connection in the electrical circuit, or a faulty Brake Lamp Switch. To fix this problem, you should visually inspect the wiring harness and connectors, checking for any damage or corrosion.

 

[jeewagon]

From the FSM it seems that the code should only be set if the cruise is turned on and then the PCM doesn't see the solenoids operating.
Could you be accidently catching the button as you are driving?

You can't just disconnect the steering wheel switches as they are resistor multiplexed and the PCM senses different voltages to determine which button has been pressed. The left switch has an additional resistor so the PCM doesn't see 5V unless the switches are disconnected which would give you a different trouble code.

It might be worth unplugging the switches and measuring the resistance of the switches with no buttons pressed. If the connector on the loom side were shorted out with a resistance of that value, the PCM should think the switches are connected, but pressing any of them would have no effect. It wouldn't therefore turn the cruise on, so shouldn't check for solenoid operation, and in turn no trouble code should be generated.

That's the way it seems it should work to me.

Thanks for all of the replies. This may be the cause. This is my first Jeep so I am not very familiar with them yet. The seller did state that the cruise had been "unhooked" and once I did more research I realized the entire servo was gone. Prior to this realization I has been pushing the cruise "on/off" button on the steering wheel to see if it would work. The cruise light in the cluster will come on for a second then turn off and I can't get it to show up again unless I shut the jeep off and restart. I may just try clearing the code with a scanner and not touching the buttons on the wheel. The CEL has been turning off on it's own and it comes back on after maybe 50 miles. I haven't tried clearing the code with a scanner yet. If it throws the code again I'll pull the switches and measure resistance.

Are you sure this is the only fault code? Because I don’t believe that that code would turn on the cel

This is not the only fault code. The only other code besides this one is a P0138 for an O2 Sensor - NTK replacements for all 4 are on the way.

Found this on the World Wide Web. Do your brake lights light?


The most common cause of this issue is a faulty Speed Control Brake Switch located at the brake pedal. Other possible causes include an open or shorted Speed Control Brake Switch harness, poor electrical connection in the electrical circuit, or a faulty Brake Lamp Switch. To fix this problem, you should visually inspect the wiring harness and connectors, checking for any damage or corrosion.

All brake lights, and lights in general, are functioning properly.