Fuel Gauge - Inaccurate Fuel Tank Level Troubleshooting
Group 62Instruments
Bulletin Number
6201 93 (3753)
Woodcliff Lake, NJ
October 1994
Product Engineering
This Service information bulletin supersedes S.I. 62 01 93 (3753) dated October 1993, which should be removed from your S.I. binder and discarded. It incorporates additional information on Fault Code 10 and a revised troubleshooting chart (changes are shown with asterisks).
SUBJECT:
Fuel Gauge Displays Inaccurate Fuel Tank Level
MODELS:
All E36
Situation:
Three separate, but related complaints may be encountered:
A) The fuel gauge displays an incorrect level. For example, the gauge appears to stick at approximately 1/2.
B) The fuel gauge does not show maximum level when the tank is filled.
C) The fuel gauge reading "drops" during cranking.
Causes:
Three causes may exist for these complaints:
**A) Fuel Level sender voltage is not accurate. This can be due to:
1) Left-hand side fuel level sender (P/N 16 14 1 180 517) sticking, causing the gauge to appear to stick at approximately 1/2.
2) Right-hand side fuel level sender (P/N 16 14 1 180 504) exhibits out-of-specification resistance, creating an implausible fuel level sender voltage when the sender is at the top of its travel (full fuel tank). **
B) Pump nozzle shuts off prematurely when filling tank, creating the incorrect impression that the fuel tank is full, and the fuel gauge does not show the maximum level.
C) Instrument cluster misinterpretation of low voltage at "ti" signal input causing a drop in fuel gauge reading during cranking. This misinterpretation is caused by Instrument Cluster being kept "awake" with ignition switched off (for example, "Key in Ignition" warning), and interpreting low voltage at pin 21, connector X16 as "continuous injection" and therefore adjusting the displayed fuel level downwards. This only applies to Instrument Clusters with Hardware Number less than 5.4 (VDO) or 10.6 (MotoMeter).
Corrections:
Because several different causes could result in the complaint of "Fuel Gauge Displays Inaccurate Fuel Tank Level: a troubleshooting chart is attached to aid in accurate and efficient diagnosis.
Before making a decision as to which of the corrective measures listed below is applied, follow the troubleshooting chart.
For Situation A:
1) E36 vehicles produced prior to 08/91 and exhibiting complaint "A" as described above should have an improved left-hand side fuel level sender (P/N 16 14 1 180 517) installed. The improved fuel level sender bears a date code stamp of "9.91" or later.
**2) Any E36 exhibiting this complaint and passing the first two steps of the troubleshooting chart, or exhibiting this complaint on an intermittent and/or non-reproducible basis, should have the fuel level senders removed and checked for proper resistance (refer to Step 4 of the troubleshooting chart).
Important Note:
An implausible fuel level sender signal will result in two indications during diagnosis with the MoDIC.
^ The word "BREAK" will be superimposed on the bar graph of the "Tank-Sensor Resistance" if the sensor voltage exceeds the operating range for more than 1 second. "Short to Negative" is displayed if the voltage falls below the operating range for more than 1 second.
^ Fault code 10 will be recorded in the event of sensor voltage exceeding or falling below the operating range for more than 1 second; however, switching the ignition "off" and then "on" again will cause a reset which erases Fault Code 10, unless it is still present. As a result, intermittently implausible fuel sensor voltages will not be retained in the Fault Memory in many cases.
It is therefore important to check the resistance of the senders (refer to step 4 of the troubleshooting chart) in the event of sporadic, non-reproducible complaints. **
For Situation B:
E36 vehicles exhibiting complaint "B" as described above should have the breather line inspected for restriction and position. Refer to Service Information bulletin 16 01 92 (3553) for this procedure.
For Situation C:
For Instrument Cluster with HW Number less than 5.4 (VDO) or 10.6 (MotoMeter) only:
Troubleshoot system as per chart and install resistor harness adapter (P/N 62 11 9 066 812) as per instructions.
Notes:
1) The Parts Department only stocks P/N 16 14 1180 517 bearing date code stamps of "9.91" or later.
2) Situations A & B cannot be rectified by the replacement of the Instrument Cluster. Instrument Cluster replacement should only be performed for an inaccurate fuel gauge complaint when troubleshooting by the chart reveals the gauge as defective (step 2a).
3) Situation C can be resolved by the installation of the resistor adapter harness (P/N 62 11 9 066 812) if the Hardware Number is below 5.4 (VDO) or 10.6 (MotoMeter). Clusters with Hardware Numbers above these limits should not have this adapter harness installed.
Warranty Information:
Parts and labor for the following repairs are reimbursable under the BMW New Car Limited Warranty of 4 Years/50,000 miles.
Situation A:
Labor for performing Instrument Cluster Self-Test, checking Tank Sender Resistance with the MoDiC, diagnosing as per the troubleshooting chart, and replacing fuel level sender(s) is to be claimed as follows:
**Description
Defect Code: 16 14 00 12 00 Fuel Sender Failed Right
Labor Operation: 16 12 000 Replacing Right-Hand (only)
Labor Allowance: 13 FRU
Defect Code: 16 14 02 48 00 Fuel Sender Failed Left
Labor Operation: 16 12 001 Replacing Left-Hand (only)
Fuel Sender
Labor Allowance: 14 FRU **
Note:
Use the following labor operation number if repairing both fuel senders:
Labor Operation: 16 12 005 Replacing both Fuel Senders
Labor Allowance: 16 FRU
Situation C:
Labor for performing Instrument Cluster Self-Test, checking Tank Sender Resistance with the MoDiC, diagnosing as per troubleshooting chart, and installing resistor adapter harness is to be claimed as follows:
(Note:
This procedure corresponds to performing steps 1, 2, 3, and 3a-3d of the troubleshooting chart.)
Defect Code: 62 11 06 18 00 Fuel gauge incorrect reading
Labor Operation: 00 50 495 Install Resistor Adapter Harness
Labor Allowance: 8 FRU
(325iC = 10 FRU)
Labor Operation: 32 34 500 Additional labor for airbag
Labor Allowance: 2 FRU
In the event that replacement of the Instrument Cluster proves necessary (step 2A), labor is to be claimed as follows:
Description
Defect Code: 62 11 06 18 00 Fuel gauge incorrect reading
Labor Operation: 62 21 001 Replace Instrument Cluster
Labor Allowance: 7 FRU
Labor Operation: 32 34 500 Additional labor for airbag
Labor Allowance: 2 FRU
Important Note:
Fuel Level Senders and/or Instrument Clusters may only be replaced for a complaint of fuel gauge inaccuracy after performing the troubleshooting detailed in the accompanying chart. Reference the step number of this chart that indicated a defective part on the warranty claim. A printout of the Instrument Cluster Identification Page must accompany all claims.
Installation Instructions for Resistor Adapter Harness
(P/N 62 11 9 066 812)
Note:
Please Read Through Completely Before Beginning Repair
1. Remove instrument cluster.
2. Cut the wire tie at the white 26-pin connector and remove the tape wrapping around the harness for a distance of approximately 20cm (8") from the white 26-pin connector.
3. Remove the contact carrier from the connector. Refer to the illustration.
4. Remove pin 22 (red/yellow wire) from the contact carrier by pressing in gently on the locking tab of the pin, using an appropriate tool, and gently pulling the wire and pin out. Refer to the illustration for step 3.
Insert the removed pin into the resistor adapter connector at pin # 1 (end with wire loop) in such a way that the tab locks in (tab facing up toward "1" on end of connector). Insert the red/yellow wire of the resistor adapter into pin 22 of the contact carrier for the white 26 pin connector. Ensure that the tab locks into place properly.
5. In the same fashion as above, remove the white/black wire from position 21 of the contact carrier and insert it into pin 2 of the resistor adapter connector. Insert the white/black wire from the resistor adapter into position 21 (pin 21) of the contact carrier.
6. Snap the locking cover onto the resistor adapter. Refer to the illustration.
7. Re-tape the harness (from the contact carrier back) in such a way that the resistor adapter connector (orange connector) is located approximately 20cm (8") from the contact carrier.
Note:
The resistor adapter connector must be positioned approximately 20cm (8") from the white 26-pin connector; if this spacing is not observed, difficulty in reinstallation of the instrument cluster will be encountered.
8. Reassemble the white 26-pin connector and secure it to the harness with a wire tie (the same as the tie removed in step 2).
9. Loop the wires from the harness (that were inserted into the resistor adapter) around the adapter and secure them to the harness with a wire tie on each side of the adapter, in such a way that the adapter is secured to the harness. Refer to the illustration for step 6.
10. Reinstall the instrument cluster.