Instruments - Impaired Diagnostics/Implausible Faults: Overview
Group 34Brakes
Bulletin Number
34 01 96
Woodcliff Lake, NJ
March 1996
Product Engineering
This Service Information bulletin supersedes S.I. 34 01 96 dated February. The attachment was omitted in error.
Please remove and discard S.I. 34 01 96 dated February 1996 from your S.I. binder.
SUBJECT:
Impaired Diagnostic Capability, Implausible Fault Codes, and Unverifiable Complaints
MODELS:
3 Series (E36)
Situation:
Isolated cases may be encountered in which:
^ Diagnosis with the BMW Service Test or MoDiC is not possible;
^ Fault codes are recorded which are not plausible; or,
^ Customer complaints are not verifiable or reproducible.
Examples of customer complaints which are either not verifiable, elude normal diagnostic procedures, or lead to the discovery of impaired diagnostic capability include:
^ Warning chime sounds once, ABS light comes on
- Warning chime sounds once, all gauges deflect to zero momentarily
- AC, Recirculation, and Rear Defroster Button LEDs are illuminated and without function
- No control of air distribution and/or heat
- No Power Window or Central Locking Functions
Vehicles Affected:
3 Series (E36) - vehicles produced prior to 10/94
Cause:
Transient voltages from wheel sensor circuits may migrate through the ABS Control Module to the TxD line, thereby affecting other systems.
Please Note:
While these transient voltages may produce malfunctions as noted here, many of these malfunctions can be produced by other, more "conventional," faults (such as loose connectors, poor grounds, low battery voltage, etc.).
These procedures do not replace conventional diagnostic procedures; however, if a vehicle is encountered which exhibits multiple indicators of this phenomenon, proceed with the "correction" portion of this bulletin.
The correction should be performed only in the case of customer complaint, or in the case of Impaired diagnostic capability.
Correction:
Three variations of this situation may be encountered, and are addressed by separately below. The determination as to which variation exists is made by performing a "Brief Test" with the BMW Service Tester or MoDiC.
Variation 1: No Control Modules Found
Variation 2: Some, but not all, Control Modules Found
Variation 3: All Control Modules Found; complaint not verifiable or eludes normal diagnostic procedures
Important!
All diagnosis must Include printouts. These printouts must be sent to the Warranty Parts Return Center to ensure claim payment. (See details In "Warranty Information" section.)
Variation 1:
If no diagnostic capability exists for any control module, unplug the ABS Control Module and try diagnosis again.
If diagnosis is possible after the ABS control module has been disconnected, proceed as follows:
^ Replace ABS Control Module.
^ Install ground wires (P/N 61 12 8 364 899) on both struts of the front suspension according to the attached instructions.
^ If some, but not all, control modules are now diagnosable, proceed to Variation 2.
^ If all control modules are now diagnosable, proceed to Variation 3.
Variation 2:
If diagnosis is not possible (Via BMW Service Tester or MoDiC) for a certain control module only, disconnect all fuses for that control module, wait thirty seconds, reconnect the fuses, and recode the module (if applicable, such as ZKE IV or IHKR). If diagnosis is still not possible, replace the control module. Typically, however, control modules that have been exposed to this transient voltage event are only rendered temporarily inoperative, and are not damaged. If diagnosis is possible after reinstalling the fuses (and recoding the module, if applicable), operate the system, and check for faults. If any faults are then discovered, they should be diagnosed and repaired. Install ground wires (P/N 6112 8 364 899) on both struts of the front suspension as per the instructions.
Note:
The IHKR system (Software Version 19) and ZKE IV/ZVM system are the two systems most frequently encountered in this variation. Please note that only IHKR Software Version 19 is affected by this correction. If earlier software versions are encountered, refer to S.I. 64 02 93 (3738).
Variation 3:
If a vehicle is encountered with complaints which are not verifiable or reproducible and leaves no faults stored in that system's fault memory (an example would be a complaint of "Warning chime sounds once and all gauges momentarily deflect to zero"), proceed as follows:
^ Print out the fault memory of every system in the vehicle and compare to the list below titled "Erroneous Faults Associated with Transient Voltages in the Wheel Sensor Circuit."
^ If one or more of these faults are discovered in conjunction with an unverifiable or unreproducible complaint, and normal diagnostic procedures do not establish a clear reason for these faults, install ground wires (PIN 6112 8 364 899) on both struts of the front suspension as per the attached instructions.
^ Clear all fault memories. (In this case the battery should also be disconnected and reconnected, and all control modules recoded.) If fault codes reappear after the installation of the ground wires, they are legitimate faults not caused by transient voltages, and must be diagnosed and repaired using normal diagnostic procedures.
Erroneous Faults Associated with Transient
Voltages In Wheel Sensor Circuit*
^ Note:
While these faults are typical of erroneous faults which can be caused by transient voltages, they can also be legitimate faults caused by problems that are Independent of such voltages.
Parts Information:
P/N Description Qty
61 12 8 364 899 Ground Wire kit 2
Warranty Information:
Parts and labor are reimbursable under the terms of the BMW New Car Limited Warranty of 4 Years/50,000 Miles.
Defect Code: 34 52 90 42 00
Labor Operation: 00 51 626
(for installing ground wires at front suspension)
Labor Allowance: 16 FRU
Additional labor and parts should be charged according to the repair performed (for example, replacement of ABS Control Module).
It is vital that all printouts (including those stating "Selected Control Unit Not Found") be sent to BMW for quality control purposes. If no parts are replaced, the printouts must be marked with the vehicle's chassis number, the Warranty Claim number and this S.I. number, 34 01 94 (4029), and returned to Warranty Processing, P.O. Box 1227, Westwood, N.J. 07675, Attn: E36 Diagnostics.
If parts are replaced, the printouts must be returned to the Warranty parts Return Center, following normal procedures. Please ensure that the printouts are marked as stated above.