Engine Controls - Altitude Sensor/Switch Information

GROUP 13
Fuel Supply

Bulletin Number
13 69 83

Montvale, NJ
October 1983
Technical Dept.

SUBJECT:
ALTITUDE CORRECTION

MODEL:
1984 318i/318iA 1984 528e/528eA
1984 533i/533iA 1984 633CSi/633CSiA
1984 733i/733iA

An altitude sensing component has been installed beginning with September 1983 production in each of the above models. The specific application for each model is outlined below.

1984 318i/318iA

The manual and automatic transmission 318i's (produced 9/83 and later) are equipped with a barometric pressure sensor. This sensor is mounted on a bracket on the air filter housing. Its operation is shown in the 1984 318i Electrical Troubleshooting Manual.

1984 528e/528eA

An "altitude switch" (controlled by barometric pressure) is incorporated into the motronic harness near the air flow meter and fuse box. This switch is "closed" at altitudes of 4000 feet (1219 meters) and above, connecting terminal # 28 of the motronic control unit to "ground".

1984 533i/533iA. 1984 633CSi/633CSiA. 1984 733i/733iA

An altitude switch (controlled by barometric pressure) is incorporated into the motronic harness near the right rear corner of the engine compartments. This switch is "closed" at altitudes of 4000 feet (1219 meters) and above, connecting terminal # 28 of the motronic control unit to "ground".

CAUTION:
The barometric pressure sensor (318i) and the altitude switch (motronic) are very similar in outward appearance. However, they must not be interchanged. The barometric pressure sense (318iT-has three wire terminals, while the altitude switch (motronic) only has two wire terminals