Component Testing

Skewed Sensor Test

1. Ignition OFF, remove the vacuum source from the sensor.
2. Ignition ON, observe and record the scan tool sensor pressure parameter. This is the first sensor reading.
3. With the J 23738-A  or J 35555  , apply 5 in Hg (17 kPa) of vacuum to the sensor. Observe and record the scan tool sensor pressure parameter. This is the second sensor reading.
4. Subtract the second sensor reading from the first sensor reading. Verify that the vacuum decrease is within 1 in Hg (4 kPa) of the applied vacuum.
   • If the vacuum decrease is not within the specified range, replace the sensor.
5. With the J 23738-A  or J 35555  , apply 10 in Hg (34 kPa) of vacuum to the sensor. Observe and record the scan tool sensor pressure parameter. This is the third sensor reading.
6. Subtract the third sensor reading from the first sensor reading. Verify that the vacuum decrease is within 1 in Hg (4 kPa) of the applied vacuum.
   • If the vacuum decrease is not within the specified range, replace the sensor.

Erratic Signal Test

1. Ignition OFF, remove the sensor.
2. Install a 3A fused jumper wire between the 5-volt reference circuit terminal C and the corresponding terminal of the sensor.
3. Install a jumper wire between the low reference circuit terminal A of the sensor and ground.
4. Install a jumper wire at terminal B of the sensor.
5. Connect a DMM between the jumper wire from terminal B of the sensor and ground.
6. Ignition ON, with the J 23738-A  or J 35555  , slowly apply vacuum to the sensor while observing the voltage on the DMM. The voltage should vary between 0-5.2 volts without any spikes or dropouts.
   • If the voltage reading is erratic, replace the sensor.