Airbag Sensor - DTCs 13 and 14 High Ground Resistance
90saab02FILE IN VOL.
S.I. Man. I
SEC. PG.
B-8 41
Subject: Surface Corrosion at Front Airbag Issue: 01/90-1206
Sensor Mountings
Application: 1988-Early 1990 9000 Models with Airbag (SRS)
Figure 1:
It is possible for surface corrosion to form under the SRS front sensor mountings (Figure 1). This corrosion can result in slight increase in the electrical resistance to ground which will set fault codes in the SRS Electronic Control Unit (ECU). These fault codes indicate a resistance to ground at the sensor that is greater than 3 ohms. The fault codes are:
^ Fault Code 0F, Front Sensor 1, Resistance to ground greater than 3 ohms
^ Fault Code 10, Front Sensor 2, Resistance to ground greater than 3 ohms
A build up of corrosion at the front sensors can also set Fault Codes 13 and 14, "Front Sensor wiring resistance too high." Before replacing either the front sensor(s) or the ECU as part of Remedy 7 (Service Manual Sec. 8:6, Airbag, page 37), perform the repair procedure listed below.
NOTE
The service procedure listed below should be performed on all affected cars as a preventative measure, as well as when a corrosion-related ground fault is indicated (SRS warning lamp Illuminated). The corrosion protection should be added either at the Pre-Delivery Inspection or at the next regular service.
Cars Affected:
1988 9000 Models with SRS
1989 9000 Models with SRS
1990 9000 Models up to VIN L1007548 or L2005626. (Cars built after these VIN's have anti-corrosion protection added in production.)
Tools Required:
Special T30 Torx Bit P/N 84 71 120
Airbag Fault Code Reader P/N 84 71 112
6 mm bottoming tap Local supply
or
Circular Wire Brush Local supply
(5/16 in. dia.)
Parts Required:
Dielectric Grease P/N 02 44 780
(Equivalent to: Ford Motorcraft Dielectric Grease, Ford P/N D7AZ-19A331-A)
Mounting Screws (qty 4) P/N 73 99 520
(Required only in limited cases--See text, P.2)
Figure 2 - Inspect for surface corrosion:
Service Procedure, Correcting or Preventing Surface Corrosion at Front Sensor Mountings
1. Remove both front sensors following the instructions in Service Manual Sec. 8:6, Airbag, page 103. Make sure the ignition is off to avoid generating spurious fault codes.
2. Once the sensors have been removed, inspect the mounting surface of the sensor, the threads of the mounting screw and the corresponding threads of the rivet nut (captive nut) in the body (Figure 2). If no surface corrosion is found, go to step 5 below.
NOTE
Do not use any chemicals in cleaning the sensor mounting surfaces or hardware. Use only clean wire brushes or taps and then blow clean with compressed air.
3. If surface corrosion is found, use a clean wire brush or fine sand paper to remove the corrosion on the contact surface between the sensor and the bcdy.
NOTE
New mounting screws, P/N 73 99 520, are required if surface corrosion that cannot be easily cleaned by wiring brushing is present on existing screws. Do not use new screws in cars where cleaning will remove corrosion.
4. Next, clean the threads of the rivet nut (captive nut) in the body. The threads of the rivet nut can be cleaned by a 6 mm x 1.0 bottoming tap, if available, or by a small diameter (approximately 5/16 in.) circular wire brush such as a valve guide brush or the brush from a firearm cleaning kit. Make sure that the threads of the tap or the bristles of the brush extend all the way to the tip so that the full depth of the rivet nut is cleaned.
5. Apply the silicone dielectric grease to the contact surlace of the front sensor, the threads of the mounting screws, and the threads of the rivet nuts.
6. Mount the front sensors according to the instructions in the Service Manual.
7. If surface corrosion has set fault codes in the SRS control unit, connect the SRS Fault Code Reader to erase the fault code(s). Follow the procedure listed in the Service Manual, Sec. 8:6 Airbag, beginning on page 26. After clearing the fault code(s), wait with the ignition on for a minimum of 35 seconds before making sure that the code(s) do not reappear.
Figure 3 - Mark the campaign plate in box B3.:
8. After all prevention or repair work has been completed, stamp the Campaign Modification Plate in box B3. Use a 3/8 in. punch with the numeral "8."
Warranty Information: For Warranty Claims use Failure Coding 85074-63-0-01-0. Labor Time Allowance is Operation Number 85074 (0.3 hour).