First of all, let's see what is already known to be able to DIY repairing the LH computer:

Saab (similar) LH information:

A list of links:

Enormous list of chips and controllers:

Some other ECM info and schematics:

Russian site with Saab related LH info:

ECU pin tables:

LH 2.4.2 connector info (regretfully Volvo specific): LH24 connector.pdf

Some info on parts and replacements:

Bosch Parts supplier:

Perfect Power ECU replacements:

Simple Digital Systems ECU replacements:

Wolf Engine management systems:

BMW L-Jetronic systems:

ECU repair companies:

928 ECU repair

All details on his website:


ECU Diagnostics & Repair Centre,
Unit 314,
Solent Business Centre,
Millbrook Road West,
Southampton, SO15 0HW

Tel: 02380 776644
Intl: +44 2380 776644
Vodafone: 07771 904 004


PHONE : (44)(0)1634 230055

FAX : (44)(0)1634 233099


We do not have that in stock but we could rebuild yours. There is always
a chance that it is not rebuildable. The cost would be $299.00 plus
Thank you,
Mark Smith
AMC internet sales manager
We now accept Visa, MasterCard and American Express

Part Werks

Sent: Wednesday, December 06, 2000 4:45 AM
To: 928
Subject: [928] 928 S4 Brain Rebuilds Now Available

It has been several years since we have been able to have the 928 S4
brains rebuilt affordably in competition with Porsche. A very specific chip
set that goes bad had became unavailable and we were unable to have these
brains rebuilt.
Right now we were able to obtain a shipment of chips and can again rebuild
these units.
We are charging $495.00 with a $200.00 core charge and a 12 month
We have already shipped one brain, and have only one other rebuild unit in
stock, after that we have no other cores. You can purchase this unit or
send your broken unit in for rebuild.
Because of the problems we have had in the past with availability of chip
sets I recommend that you jump to the head of the line if you are needing a
brain or just want to stock an extra one.

Part Werks of Chicago

Part Werks of Chicago Inc
324 Henderson Ave Bldg 4
Joliet Illinois
USA 60432-2595
Tel: 815-462-3000
Fax: 815-462-3006


Firma ACM

I'm passing on a message from a German 928 owner ....
I think this message could be important for any S4, GT, GTS driver. These
cars use the Bosch LH-Jetronic fuel injection controller.

After 10 to 15 years lifetime the first controllers are beginning to stop
working correctly. One reason for this is the Hybrid-chip which is no
longer available. A new controller is more expensive than 2000 € (Euro).

PFForum-members [a German language forum similar to Rennlist] wrote about
a company (ACM Elektronik) which is able to repair all controllers. This
information comes from a discussion with Mr. Müller from the ACM
Elektronik company:

If you have problems with your LH-controller, possible symptoms are:

- The fuel-injector-valves are ticking if ignition is on.
- If you remove your foot from the accelerator, the revolutions are higher
than 2000 rpm and the car is coasting, the fuel-calculator didn't show 0,0 litres/km.
- No smooth idle
- Air/fuel-mixture: too rich
- The engine won’t run at higher than 3000 rpm
- Automatic Transmission: no RPM regulation when switching from "D" to "N" or "P".
- Engine doesn't run. The Spark plug is dry and is sparking.

Mr. Müller changed the original EPROM with a check EPROM and tests all
functions with his own software. He said he knows the controller like he
build it by himself. Electronic components which are often fail the would
be changed as part of the service.

The price for checking a controller is 50€ plus shipping. 350 for a repair/swap.
Firma ACM
Herr Müller
+ 49 62997 629462


JDS Porsche

John Speake is located in the UK, and repairs both LH and MAF units for the Porsche 928

There is more info on my website at URL:  LH ecu repair tip page 436.htm



ECU rebuilt Cost $260 . If core bad $340 @Full Logic ECU Phone Number

(866)-573-2012.Iwill get mine back Sept 12 hope it will work

Bill Croft


Electronik Repair, Inc.

is a source of LH-Jetronic module repair. Look to the website at

We have common LH module failure symptoms listed on the main page and a tech tip section in the service page, good tips for determining if your module or some other item is going bad.

Rich Andrade