Check engine light



I have an 90,000 miles on my 2003 Audi A6 Quattro. Realy like the car. But over the years have had nunerous electrical problems. Recently the “check engine light” came on. The dealer said diagnostics indicate a faulty sensor in the tourque converter. The converter has to be changer to fix the problem($3200). The light comes on and off mostly on. I’m wondering if it is possible to remove the alarm point for the tourque converter? The vehicle shifts fine and gas mileage is good. I’m not going to have the converter replaced and don’t want the alarm to mask some other problem.


How often, if ever, has the transmission fluid been changed? Depending on the code present maybe this issue is related to aged fluid if it has never been changed.

If the answer is never then the fluid should have been changed about 60k miles back.

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here. 

Lets get a better idea of what is going on.  

Don't forget to provide the answers OK's questions.


The Audi dealer read the code that indicated a torque converter problem. Because I have no transmission problems and the CEL is intermittent, it appears to me to be a faulty sensor.


No that’s not what it means. And there isn’t “the” code for a torque converter problem. There are lots of different codes. A few will be about the torque converter. Other codes might be interpreted by some techs as having to do with the torque converter. So your reference is vague. Reporting the very specific code (format “P1234”) may help people help you.

Here’s a list of codes having to do with transmission functions - admittedly a minority would bring up suspecting a torque converter problem. But these are also just the generic codes - Audi almost certainly has more that are specific to their transmissions:

DTC Codes - P0700-P0899 - Transmission

* P0700 Transmission Control System Malfunction
* P0701 Transmission Control System Range/Performance
* P0702 Transmission Control System Electrical
* P0703 Torque Converter/Brake Switch B Circuit Malfunction
* P0704 Clutch Switch Input Circuit Malfunction
* P0705 Transmission Range Sensor Circuit malfunction (PRNDL Input)
* P0706 Transmission Range Sensor Circuit Range/Performance
* P0707 Transmission Range Sensor Circuit Low Input
* P0708 Transmission Range Sensor Circuit High Input
* P0709 Transmission Range Sensor Circuit Intermittent
* P0710 Transmission Fluid Temperature Sensor Circuit Malfunction
* P0711 Transmission Fluid Temperature Sensor Circuit Range/Performance
* P0712 Transmission Fluid Temperature Sensor Circuit Low Input
* P0713 Transmission Fluid Temperature Sensor Circuit High Input
* P0714 Transmission Fluid Temperature Sensor Circuit Intermittent
* P0715 Input/Turbine Speed Sensor Circuit Malfunction
* P0716 Input/Turbine Speed Sensor Circuit Range/Performance
* P0717 Input/Turbine Speed Sensor Circuit No Signal
* P0718 Input/Turbine Speed Sensor Circuit Intermittent
* P0719 Torque Converter/Brake Switch B Circuit Low
* P0720 Output Speed Sensor Circuit Malfunction
* P0721 Output Speed Sensor Range/Performance
* P0722 Output Speed Sensor No Signal
* P0723 Output Speed Sensor Intermittent
* P0724 Torque Converter/Brake Switch B Circuit High
* P0725 Engine Speed input Circuit Malfunction
* P0726 Engine Speed Input Circuit Range/Performance
* P0727 Engine Speed Input Circuit No Signal
* P0728 Engine Speed Input Circuit Intermittent
* P0730 Incorrect Gear Ratio
* P0731 Gear I Incorrect ratio
* P0732 Gear 2 Incorrect ratio
* P0733 Gear 3 Incorrect ratio
* P0734 Gear 4 Incorrect ratio
* P0735 Gear 5 Incorrect ratio
* P0736 Reverse incorrect gear ratio
* P0740 Torque Converter Clutch Circuit Malfunction
* P0741 Torque Converter Clutch Circuit Performance or Stuck Off
* P0742 Torque Converter Clutch Circuit Stock On
* P0743 Torque Converter Clutch Circuit Electrical
* P0744 Torque Converter Clutch Circuit Intermittent
* P0745 Pressure Control Solenoid Malfunction
* P0746 Pressure Control Solenoid Performance or Stuck Off
* P0747 Pressure Control Solenoid Stuck On
* P0748 Pressure Control Solenoid Electrical
* P0749 Pressure Control Solenoid Intermittent
* P0750 Shift Solenoid A Malfunction
* P0751 Shift Solenoid A Performance or Stuck Off
* P0752 Shift Solenoid A Stuck On
* P0753 Shift Solenoid A Electrical
* P0754 Shift Solenoid A Intermittent
* P0755 Shift Solenoid B Malfunction
* P0756 Shift Solenoid B Performance or Stock Off
* P0757 Shift Solenoid B Stuck On
* P0758 Shift Solenoid B Electrical
* P0759 Shift Solenoid B Intermittent
* P0760 Shift Solenoid C Malfunction
* P0761 Shift Solenoid C Performance or Stuck Off
* P0762 Shift Solenoid C Stuck On
* P0763 Shift Solenoid C Electrical
* P0764 Shift Solenoid C Intermittent
* P0765 Shift Solenoid D Malfunction
* P0766 Shift Solenoid D Performance or Stuck Off
* P0767 Shift Solenoid D Stuck On
* P0768 Shift Solenoid D Electrical
* P0769 Shift Solenoid D Intermittent
* P0770 Shift Solenoid E Malfunction
* P0771 Shift Solenoid E Performance or Stuck Off
* P0772 Shift Solenoid E Stuck On
* P0773 Shift Solenoid E Electrical
* P0774 Shift Solenoid E Intermittent
* P0780 Shift Malfunction
* P0781 1-2 Shift Malfunction
* P0782 2-3 Shift Malfunction
* P0783 3-4 Shift Malfunction
* P0784 4-5 Shift Malfunction
* P0785 Shift/Timing Solenoid Malfunction
* P0786 Shift/Timing Solenoid Range/Performance
* P0787 Shift/Timing Solenoid Low
* P0788 Shift/Timing Solenoid High
* P0789 Shift/Timing Solenoid Intermittent
* P0790 Normal/Performance Switch Circuit Malfunction
* P0801 Reverse Inhibit Control Circuit Malfunction
* P0803 1-4 Upshift (Skip Shift) Solenoid Control Circuit Malfunction
* P0804 1-4 Upshift (Skip Shift) Lamp Control Circuit Malfunction


Thanks for the information. I’m going to find out what the failure code is and check it against your list. I’ll get back to you.


The code is P0741, which indicates “tourque converter clutch circuit performance or stuck off”. sporadic 1 event. As I stated it comes in for several hours or days then clears out.


Many of these TCC solenoids can be tested and replaced if they are found to be faulty WITHOUT replacing the torque converter or transmission. Find another shop ASAP.


That’s exactly what I am thinking.

I once cured one of these kinds of codes with 2 drops of the transmission pan in relatively quick succession.