EML light and a few codes popped up. Any ideas on what to change first?

[R1pilot]

2004 SMG with 161k miles.
Engine is stock except for euro headers, euro cat, supersprint exhaust.

I see a lot of threads pointing to changing the TPS sensors and also the gas pedal, but before throwing money at the car I thought I ask here to see what the thoughts are.


Got an EML light while driving. It will go away if you shut off the car and turn on again, only to come back after a bit. It always happens around the same part of my commute.

The next day about 20 miles after the EML light I got the "Service engine soon" light ... car was still running ok on the interstate, but as I slowed down and got to about 20 mph, the traction control light and "BRAKE" light popped up and the car went into limp mode.

Reading codes with INPA I got:

- 230 EGAS Target actual comparison
- 79 EGT Sensor
- 120 Throttle valve potentiometer comparison
- 118 Throttle valve potentiometer 1
- 119 Throttle valve potentiometer 2
- 121 Both Throttle valve potentiometers
- 94 Internal index 241

I also checked with the Schwaben tool and got these:

- 78 DME Electric throttle potentiometer signal
- 76 DME Electric throttle signal potentiometer throttle
- 77 DME Electric throttle signal potentiometer servomotor
- 79 DME Electric throttle both

Thanks!

[Obioban]

Start with the easy TPS-- the one over the oil filter housing. It's probably that, as it seems to be that one 95% of the time.

If that doesn't take, move on to the one under the intake manifold, since you already own the part (same as the one above the oil filter housing).

Failing that, leave the new part there (because it's a PITA to get to), throw the good part in your trunk as a spare (my always with me spare parts kit in the trunk is an old good coil and an old good TPS), and replace your gas pedal.

[sapote]

230: DME: Electric throttle: setpoint/actual value deviation, means pedal command data is not same as throttle feedback data.
79 exhaust T sensor; don't know if this is the one that triggered the SES light
120: the two throttle sensors are not in good comparison.
121: DME: Electric throttle: both potentiometers faulty. I don't believe both are bad at the same moment
94: intake vanos timing out of spec. This one probably set the SES light on.

I think only one throttle sensor is bad, not the pedal. Make sure there is no interference on the throttle rod for its full range of motion.

[R1pilot]

Thanks guys! Quick question, do I need to reset any adaptations after changing the tps?

I have a spare engine out of a 2001 that was pulled at 89k miles. I am going to check if the sensor is the same and if so will swap it out to test out.

I will check the throttle rod but the last time I removed the intake or touch anything there was about 30k miles ago when I did the starter.

I will report back with my findings.

[sapote]

Thanks guys! Quick question, do I need to reset any adaptations after changing the tps?

Yes, as they are not exactly going to give the same value at the same position.

[R1pilot]

Small update.

Changed the front TPS sensor with one from the spare engine. My son took the car to school today, about 40 miles roundtrip and no lights.

I always get the EML light to come up within less than a mile on a certain part of my commute, so I will report back on Monday with final results.

Thanks!