Test E - Barometric Pressure (BP) Sensor
NOTE:
Barometric pressure sensor output is digital and cannot be measured without special equipment. Perform harness check before replacing sensor.
- Code 22. Turn ignition off and wait 10 seconds. Disconnect barometric pressure (BP) sensor. Inspect for damaged pins, corrosion and loose wires. Repair as required. Turn ignition on. With DVOM on 20 volt scale, measure voltage between sensor harness voltage reference circuit and battery negative post. If 4-6 volts, go to next step. If less than 4 volts, service open in voltage reference circuit and retest. If still less than 4 volts, replace ECA. Reconnect sensor and repeat Quick Test. If voltage is greater than 6 volts, go to Test C.
- With sensor disconnected, turn ignition on. With DVOM on 20 volt scale, measure voltage between sensor harness signal return circuit and battery positive post. If 10 volts or more, go to next step. If less than 10 volts, repair open in signal return circuit, reconnect sensor and repeat Quick Test.
- Turn ignition off and wait 10 seconds. With sensor disconnected, disconnect 60-pin connector at ECA. Inspect for damaged pins, corrosion and loose wires. Service as required. Install breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure resistance between sensor harness barometric pressure signal circuit and box pin 45. If reading is less than 5 ohms, remove breakout box and go to next step. If 5 ohms or more, repair open in barometric pressure signal circuit. Remove breakout box and reconnect ECA and sensor. Repeat Quick Test.
- Turn ignition off. Breakout box removed; ECA and sensor disconnected. With DVOM on 200,000 ohm scale, measure resistance between sensor harness barometric pressure signal circuit and signal return circuit. Then between barometric pressure signal circuit and voltage reference circuit. If either reading is less than 10,000 ohms, repair short. Reconnect sensor and ECA and repeat Quick Test. If both readings are 10,000 ohms or more, reconnect harness to ECA and substitute a good sensor and repeat Quick Test. If code 22 appears, replace ECA, using original sensor, and repeat Quick Test.
- Continuous Monitor Code 22. Using Continuous Monitor mode, observe volt/ohmmeter for fault indication while doing the following: Connect vacuum pump to barometric pressure sensor and slowly apply 25 in. Hg vacuum. Slowly bleed vacuum off and lightly tap sensor then wiggle sensor connector. If no fault is indicated, go to next step. If fault is indicated, disconnect and inspect harness and sensor connector. Replace sensor and repeat Quick Test.
- Observe volt/ohmmeter while doing the following: Beginning at barometric pressure sensor, wiggle, shake or bend small sections of harness while working way to dash panel. Then repeating process from panel to ECA. If fault is indicated, isolate and repair problem and repeat Quick Test. If no fault indicated, go to next step.
- Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA. Inspect harness terminals and ECA pins for damage. Repair as required. If terminals and pins are okay, fault cannot be duplicated at this time. Continuous Code 22 test complete.