Thread: 2006 GP GXP issues

I was wondering if anyone has had any issues after running a Diablo Tuner on their car? I turned the DOD off. After driving awhile I got the messages "service traction contol", "service stability" and I'm getting the code P0121. I know the code is for a TPS but the cars are drive by wire, so which sensor is going bad? The throttle body actuator or the pedal position sensor? This morning she was sitting at a traffic light and almost died till she tapped on the gas and it stayed running. It's happened a few other times as well. Any help would be great. Thanks

DTC P0121 Throttle Position (TP) Sensor 1 Performance

Circuit Description

The throttle body assembly contains 2 throttle position (TP) sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies the TP sensors with a common 5-volt reference circuit, a common low reference circuit, and 2 independent signal circuits.
The TP sensors have opposite functionality. TP sensor 1 signal voltage decreases from above 4 volts at idle to below 1 volt at wide open throttle (WOT). TP sensor 2 signal voltage increases from below 1 volt at idle to above 4 volts at WOT.
The ECM compares the signal of the TP sensor 1 and TP sensor 2 through the entire range. If the ECM detects a predetermined difference between sensor 1 and sensor 2, or a predetermined difference from the predicted range, this DTC sets.

Conditions For Setting The DTC

• The TP sensor 1 disagrees more than 9 percent from TP sensor 2.
• The TP sensor 1 disagrees more than 9 percent from the predicted value.
• The above conditions are met for less than 1 second.

Conditions For Running The DTC

• DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0128, P0335, P0336 are not set.
• The engine speed is more than 450 RPM.
• The engine coolant temperature (ECT) is between 70-125°C (158-257°F).
• The intake air temperature (IAT) is between -7 and +125°C (+19 and +257°F).
• DTC P0121 runs continuously when the above conditions are met.

__________________________________________________ _____________________________

Most intermittent conditions are caused by faulty electrical connections or wiring. Inspect for the following items:

• Wiring broken inside the insulation
• Poor connection between the male and female terminal at a connector
• Poor terminal to wire connection-Some conditions which fall under this description are poor crimps, poor solder joints, crimping over the wire insulation rather than the wire itself, and corrosion in the wire to terminal contact area, etc.
• Pierced or damaged insulation can allow moisture to enter the wiring causing corrosion. The conductor can corrode inside the insulation, with little visible evidence. Look for swollen and stiff sections of wire in the suspect circuits.
• Wiring which has been pinched, cut, or its insulation rubbed through may cause an intermittent open or short as the bare area touches other wiring or parts of the vehicle.
• Wiring that comes in contact with hot or exhaust components
• Refer to Inducing Intermittent Fault Conditions in order to duplicate the conditions required, in order to verify the customer concern.
• Refer to Testing for Electrical Intermittents for test procedures to detect intermittent open, high resistance, short to ground, and short to voltage conditions.
• Refer to Scan Tool Snapshot Procedure for advanced intermittent diagnosis and Vehicle Data Recorder operation.

__________________________________________________ __________________________________________________ ______________________________

Above is a bunch of information from my shop software. Basically, I highly doubt it has anything to do with your Diablo (even though I hate those things).
It sounds to me like you will most likely end up replacing the throttle body.

Hope this helps,
Brandon

Originally Posted by bfurches

DTC P0121 Throttle Position (TP) Sensor 1 Performance

Circuit Description

The throttle body assembly contains 2 throttle position (TP) sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies the TP sensors with a common 5-volt reference circuit, a common low reference circuit, and 2 independent signal circuits.
The TP sensors have opposite functionality. TP sensor 1 signal voltage decreases from above 4 volts at idle to below 1 volt at wide open throttle (WOT). TP sensor 2 signal voltage increases from below 1 volt at idle to above 4 volts at WOT.
The ECM compares the signal of the TP sensor 1 and TP sensor 2 through the entire range. If the ECM detects a predetermined difference between sensor 1 and sensor 2, or a predetermined difference from the predicted range, this DTC sets.

Conditions For Setting The DTC

• The TP sensor 1 disagrees more than 9 percent from TP sensor 2.
• The TP sensor 1 disagrees more than 9 percent from the predicted value.
• The above conditions are met for less than 1 second.

Conditions For Running The DTC

• DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0128, P0335, P0336 are not set.
• The engine speed is more than 450 RPM.
• The engine coolant temperature (ECT) is between 70-125°C (158-257°F).
• The intake air temperature (IAT) is between -7 and +125°C (+19 and +257°F).
• DTC P0121 runs continuously when the above conditions are met.

__________________________________________________ _____________________________

Most intermittent conditions are caused by faulty electrical connections or wiring. Inspect for the following items:

• Wiring broken inside the insulation
• Poor connection between the male and female terminal at a connector
• Poor terminal to wire connection-Some conditions which fall under this description are poor crimps, poor solder joints, crimping over the wire insulation rather than the wire itself, and corrosion in the wire to terminal contact area, etc.
• Pierced or damaged insulation can allow moisture to enter the wiring causing corrosion. The conductor can corrode inside the insulation, with little visible evidence. Look for swollen and stiff sections of wire in the suspect circuits.
• Wiring which has been pinched, cut, or its insulation rubbed through may cause an intermittent open or short as the bare area touches other wiring or parts of the vehicle.
• Wiring that comes in contact with hot or exhaust components
• Refer to Inducing Intermittent Fault Conditions in order to duplicate the conditions required, in order to verify the customer concern.
• Refer to Testing for Electrical Intermittents for test procedures to detect intermittent open, high resistance, short to ground, and short to voltage conditions.
• Refer to Scan Tool Snapshot Procedure for advanced intermittent diagnosis and Vehicle Data Recorder operation.

__________________________________________________ __________________________________________________ ______________________________

Above is a bunch of information from my shop software. Basically, I highly doubt it has anything to do with your Diablo (even though I hate those things).
It sounds to me like you will most likely end up replacing the throttle body.

Hope this helps,
Brandon

Thanks for the info. That was a lot of good info. I'm only running my programmer to turn the DOD off. I got tired of adding oil so I'm trying it out. Thanks again!

Originally Posted by 91parkave

First try cleaning your throttle body out. ensure the blade can move freely through the bore. A light 2000 grit sandpaper by hand can smooth it Out

Use scotch brite instead of sandpaper

Originally Posted by 91parkave

the bore needs to be more polished than scuffed. this keeps carbon from sticking causing issues like this in the first place

Thanks everyone.