Subject: 1998 E39 523i throttle problems Author: matt535i : 205 posts Posted on: 2010-09-04 03:56:06

Ok, this is on behalf of a friend with an E39 525i.

(dont know if you got the 523i model in the states, but it has the 2.5L inline 6 cylinder, and is a very similar car to the 528i, apart from the engine size)

The check engine light is on, and the car starts and idles ok. But as soon as you give it some throttle, it revs to 1800rpm and then begins backfiring and hits a wall it will not rev past. The ECU has gone into limp-home-mode I think.

Pulled the codes, and it gives me 3 distinct ones:

*Throttle pedal potentiometer no signal.
*Electric throttle solenoid no signal.
*two stage engine fan- one stage not functional.

Not worried about the fan code for the moment. I need to know how the throttle pedal potentiometer and throttle position sensor is laid out on a 528i (pretty much the same to this 523i) so I can understand what to unbolt, and what to replace. My friend doesnt have much cash at the moment, so I'm trying to do what I can for him, without telling him to go buy new $400 throttle position sensors, etc. (Even though there may be no other option in the end)

Thoughts?



1996 E39 535i- 3.5L M62 V8, 5HP24 stept. trans
Exterior: #303 Cosmos Black Metallic + Shadowline trim
Interior: Black on black leather + factory 'High Polished Black' interior trim
Wheels: silver BBS RK 17x9.5" Tires: Maxxis MA-Z1
M-Sport suspension, TV-in motion, High OBC unlocked, 'Grom' USB stick-compatible audio system.

• 1998 E39 523i throttle problems - matt535i 2010-09-04 03:56:06 (419 views)