Did I screw up my A4 by using VCDS incorrectly?

[Tongpo]

Hey guys, I've got a 2002 A4 3.0 MT, and I think I may have screwed it up by playing around with VCDS.

A week ago the ABS and ESP lights came on along with the 01435 - Brake Pressure Sensor 1 (G201) DTC. I replaced the brake pedal switch, hoping that would be a quick and cheap fix for this issue, but that didn't solve the problem.

A recommendation I found when searching this forum was to use VCDS to perform a basic settings adaptation of the G201 sensor in the ABS module (I may not have the wording correct). Without doing enough homework, I went into the ABS basic settings and scrolled up and down the groups, looking for G201 sensor. After reading up on the RossTech Wiki page after the fact, I now realize I should have selected a specific group rather than scroll through them all. After scrolling up and down in the ABS groups, two things occurred:

1) The car is very difficult to start. It turns over fine, but doesn't want to fire up. I found that keeping the gas pedal floored while starting helps, but it still has turn over a dozen or so times before it fires up, and when it fires up it sputters for a few seconds, acting and smelling like its flooded. Once it gets running, it runs fine. Surprisingly, it throws no codes for this behavior.

2) I got the 01486 - System Function Test Activated code. I researched this and found the procedure to complete the test (http://wiki.ross-tech.com/wiki/index..._Function_Test). I completed the test and the 01486 code cleared and the ABS and ESP lights went out.

Completing the system function test had no impact on the starting issue.

Is my starting issue due to my playing around with VCDS? If not, it's a heck of a coincidence. If it is, how do I correct the situation? Will disconnecting the battery for some period of time reset things, or do I need to do something with VCDS to set things right?

The only other code up is 17704 - Error in Mapped Cooling System (check Temp-Sensor and Thermostat) P1296. This has been up for over a week now, and was up before the starting problems started, so I don't think it has anything to do with my starting issues. Tomorrow, I am going to replace the G2/G62 4 wire coolant temperature sensor to, hopefully, correct this issue.

Thanks for any insight anyone can provide.

[KHARDa4]

A bad coolant temp sensor that is input for the ecm could cause a hard start like you are having. I don't know the 3.0 but I would start by checking the cts wiring if all is good replace it clear codes and fire it up go from there.

EDIT: if you clear the code and crank does it start any differently?

[diagnosticator]

The hard starts are not caused by your misguided VCDS use. As stated already, the cooling system performance DTC is most likely associated with a coolant temp sensor fault, and can cause the hard starts.

[Tongpo]

I replaced the G62 CTS this morning and the old Audi now fires right up.

Thanks KHARDa4 and diagnosticator for your help.

[diagnosticator]

I replaced the G62 CTS this morning and the old Audi now fires right up.

Thanks KHARDa4 and diagnosticator for your help.

Good job! BTW, the Brake Pressure Sensor G201 is screwed into the aluminum ABS hydraulic control valve block/module. If a brake pressure sensor DTC continues to occur after clearing all DTCs, then either the wiring to the sensor is faulty or the sensor itself is faulty.

[KHARDa4]

I replaced the G62 CTS this morning and the old Audi now fires right up.

Thanks KHARDa4 and diagnosticator for your help.

No problem, glad you got it worked out.