Variable Bosch MAP Sensor Replacement
Introduction: The Varimap pressure sensor is a direct replacement for the Bosch MAP sensors found in many 1990's era ECU's. The Varimap sensor is a clean sheet design using extremely fast and accurate components to make it the most flexible, highest performance map sensor solution on the market. Required Tools:
- T20 Male Torx Driver
- T10 Male Torx Driver
- Small Flat Blade Screw Driver
- Soldering Station (Attached to a competent user.)
Installation (Applies to Audi AAN/ADU/3B style ECUs):
- Remove 6 torx bits from the bottom of the case.
- Using small screw driver pry all tabs up holding case halves together.
- Remove center pins from 3 round plastic clips.
- Take case top and bottom off of the ECU boards.
- Spread ECU board halves apart.
- De-solder and remove stock MAP sensor, leave the plastic mounting base attached to the ECU board, as shown here:
- Install (solder) new 3-pin header for Varimap signal cable into the ECU board, as shown here, note the position of the key tab on the header:
- Clip Varimap sensor into the stock MAP sensor bracket using the top 2 holes in the bracket, attach supplied cable to both 3 pin headers, and reconnect map sensor signal hose to the Varimap:
Configuring the Varimap: The Varimap has 3 separate ranges that it can be used in. This is designed to be matched to the tuning provided for proper boost control and protection. Do not install a varimap in any range that the tune is not calibrated for! If you do not know what map sensor range you need to be using contact your tuner! Range selection is very simple, there is a single jumper installed on the board, the positions are labeled 2.5,3,4. This correlates to a bosch 250kpa sensor, 300kpa sensor, or 400kpa sensor.
The active range selection can be verified without completely pulling the ECU apart with the range display LED. This LED will indicate what setting the Varimap is currently using by blinking a corresponding number of blinks. 2 blinks followed by a pause = 250kpa, 3 blinks followed by a pause=300kpa, 4 blinks followed by a pause=400kpa. The ECU must be powered up for this to work of course, this can be done in the car with only the top cover removed from the ECU. The LED is extremely bright and can be easily seen through the board above the map sensor, making range verification very easy.