Fault TRACINGB23FT 1983 M/Y

The air mass meter for above model year has an aluminum housing. The housing is marked with Bosch Part Number 0 280 212 002.

Connector configuration as illustrated.

CAUTION: The two types of air mass meters described in this Service Bulletin are not interchangeable.



Check ground(s)

- Connect an ohm-meter between terminal 36 and ground, and between terminal 6 and ground.

Meter should show less than 1 ohm resistance in both cases. Check wiring continuity if value is higher.



Check voltage supply

- Turn ignition ON.

- Connect a volt meter between terminal 9 and ground

Meter should show battery voltage. Check wiring and system relay if lower than battery voltage.



Check CO-adjustment screw

- Turn ignition ON.
- Connect a voltmeter between terminal 14 at LH control unit and ground.

Meter should show 0 to 2.6 volts, depending on CO-screw position.

0 volts = max. lean position
2.6 volts = max. rich position

- Turn screw on air mass meter and check if voltage changes.

If no voltage or no variation when screw is turned, check wiring continuity.

NOTE: Adjustment screw must be resealed after adjustment.



Check air mass meter output

- Turn ignition ON.
- Connect a voltmeter between terminal 7 at the LH control unit and ground.

Meter should show 1.6 volts.

- Start engine and warm up to operating temperature (AC off).

- Check output at idle (750 rpm). Meter should show 2.7 volts.

- Increase engine speed to 3,500 rpm. Output should increase to 3.5 volts

Check wiring continuity if out of specification.



Burn off function

Engine running at operating temperature.

- Connect a volt meter between terminal 8 and ground.
- Increase engine speed to 2,500 rpm.
- Close throttle and let engine slow down to idle speed.

- Turn ignition OFF.

After approximately 4 seconds, meter should deflect for 1 second. If no reading, check wiring continuity.
Protective screen replacement

The protective screen(s) can be replaced on air mass meter with aluminum housing, 1984 M/Y.

Description Part No. Qty

Screen 1357985-9 1 or 2
(as needed)



Remove lock ring and screen
- Pry out the lock ring with a small screwdriver.

- Install screen and lock ring Make sure the lock ring is fully inserted in the groove.

INSTALL

- rubber connector cover at air mass meter
- connector cover at LH control unit
- kick panel