Signal Too Low - Intermittent Fault

Checking Wiring







Check the engine control module (ECM) and atmospheric pressure sensor connectors for contact resistance and oxidation according to Checking wiring and terminals - Intermittent faults.

Check in particular for damage, or loose terminal pins.

Check the signal cable between engine control module (ECM) terminal 18 and atmospheric pressure sensor terminal 3 for an intermittent short-circuit to ground. Remedy according to Checking wiring and terminals - Intermittent faults and for an intermittent open-circuit according to Checking wiring and terminals - Intermittent faults.

Check the voltage cable between engine control module (ECM) connector terminal 78 and atmospheric pressure sensor terminal 1 for an intermittent open-circuit. Remedy according to Checking wiring and terminals - Intermittent faults.

The supply voltage should be 5 V.

Checking Wiring And Terminals

Other information:
- To connect the breakout box, Connecting the Breakout Box, ECM (EMS 2000)
- To replace the atmospheric pressure sensor, see Replacing the air conditioning (A/C) system pressure sensor.