I just finished reinstalling the intake manifold after cleaning the valves and went to start the car. It starts for about 2 seconds before shutting itself down. It throws 6 pending codes. P0503 - Speed (RPM) sensor erratic/high, C0203, C1103, C1403, C1203, C1300. I don't think I did anything to mess with the speed sensor. Any ideas?


startup video: https://www.dropbox.com/s/0cjn7k4ny480y70/A4%20Startup.mov?dl=0

Engine Stats right before shutdown: Engine Stats

OBD DTC: OBD Trouble Codes

UPDATE #2: So it turns out that my OBD reader was giving me the wrong codes. The real codes were P0351-354, all referring to the ignition coils (which I replaced at the same time). The car starts, registers the fault and then shuts down the injectors. They are the correct coils, and obviously they are getting current because the car starts.. why would it register those codes. I've reseated them checked all the connections. Unfortunately I didnt keep the old coils.

  • When you clear the codes, do all 6 come right back upon attempted restart? Commented Jun 21, 2015 at 20:54
  • they do, I've repeated it about 8 times now Commented Jun 21, 2015 at 20:57
  • Did you recheck the connection at the sensor to ensure complete and secure connection? Commented Jun 21, 2015 at 20:59
  • to be honest I'm not even sure where that sensor is. I've been googling for a while trying to find a diagram. Commented Jun 21, 2015 at 21:00
  • The P0503 says it's for the vehicle speed sensor, yet what you are giving me and the notes about it suggest it's an engine speed sensor (such as 4 tics per engine revolution). Doesn't make sense to me. I'll continue looking though. Commented Jun 21, 2015 at 21:48

3 Answers 3


You can try replacing the Engine Crank Angle Sensor, which I believe is the one which is playing erratic. The sensor looks like this:

enter image description here

So it is the one you are looking at in the picture. Who knows why it's gone bad, but with the code you mentioned, this seems like the culprit.

This is a very good video on the replacement of the sensor. The only thing I'd say about what he does to replace it is, don't mess with the throttle while trying to crank your engine. On many (not sure about the VAG engines), your throttle position sensor will get screwy readings when you do that and your car won't run right again until you do a reset.

Overall, this is a very easy thing to do. You may even be able to do the exchange from the top side (instead of removing the cover).

  • Yeah, I found that sensor down on my crankcase, but the problem is that I wasn't working anywhere near that and the car was running fine prior to me taking the intake off. The odds of that going bad at the exact same time just seems like an unlikely coincidence. But thanks for your detailed answer Commented Jun 26, 2015 at 14:59
  • You could be right, but in this case you might want to apply Ockham's razor. In this case, this is the simple theory which would explain. That's where the engine code points to. You could first look to ensure you have proper connectivity along the wiring involved with the sensor. Seeing as how it is not a completely fault, I doubt wiring issues would have anything to do with it. I have seen stranger issues appear by the same manner as what you are suggesting. Commented Jun 26, 2015 at 15:17
  • I agree and I did check the wires and connection up to the bundle and they all seemed fine. Commented Jun 26, 2015 at 15:19
  • Since the problem is intermittent/erratic/high and not a complete failure, the only way you'd be able to tell is through replacement. I absolutely hate remove & replace mechanicing, but in this case, it may be your only choice. Commented Jun 26, 2015 at 15:23
  • I also get a lot of C-codes. Do you think there is any chance that these codes are thrown in the event of an unsuccessful start. Also my friend broke the clip on the camshaft position sensor, but the pins all seemed fine. Maybe that is the cause of the code..? Commented Jun 26, 2015 at 15:29

All your codes are from different areas but can be from the same place. It's ABS, Brakes, Axle solenoids and so on.

I suppose you or your mechanics forgot to connect one of big connectors with several wires that are causing your problems. Try to look for unplugged connectors under your trunk

Good luck!


Is the ABS/ESP control unit located in the vicinity of the intake manifold? Did you try removing the connector of ABS/ESP control unit?Check whether the ABS/ESP control unit is communicating with the scanner. All the fault codes point to issue in ABS/ESP control unit

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