Pinpoint Test A: Electronic Engine Controls Pinpoint Test

1. A1: PERFORMANCE CHECK OF HEATED OXYGEN SENSOR(S) (HO2S) 
   NOTE:

   • Refer to the Heated Oxygen Sensor (HO2S) location  article for information on Heated Oxygen Sensor (HO2S) locations
   • Oxygen sensors will become functional at different times, depending on their location within the exhaust system and the previous drive cycles
   1. Refer to the HEATED OXYGEN SENSOR (HO2S) ACTIVATION REQUIREMENTS  and DRIVE CYCLE  articles for information on Heated Oxygen Sensor (HO2S) activation requirements and drive cycles
      NOTE: Pre catalyst oxygen sensor - Signal displayed in mA - Signal changes either side of 0mA as fueling changes from lean to rich
   2. Using the manufacturer approved diagnostic system check the live data signal Oxygen Sensor Current Bank 1 - sensor 1 (low res)
   3. Using the manufacturer approved diagnostic system check the live data signal Oxygen Sensor Current Bank 2 - sensor 1 (low res)
      NOTE: Mid and post catalyst oxygen sensor - Signal displayed in Volts - Signal changes between 0 and 1 volt as fueling switches from lean to rich
   4. Using the manufacturer approved diagnostic system check the live data signal Oxygen Sensor Output Voltage Bank 1 - sensor 3
   5. Using the manufacturer approved diagnostic system check the live data signal Oxygen Sensor Output Voltage Bank 1 - sensor 2
   6. Using the manufacturer approved diagnostic system check the live data signal Oxygen Sensor Output Voltage Bank 2 - sensor 2
   7. Using the manufacturer approved diagnostic system check live data signal Oxygen Sensor Output Voltage Bank 2 - sensor 3
   8. View the output signals for each Heated Oxygen Sensor (HO2S). When active each sensor can be seen reacting to changes in engine speed/load

   Observe the oxygen sensor signal responsible for the DTC. Is the sensor functioning correctly?

   Yes:  No failure is found. Clear DTCs and perform road test to confirm no fault is present. Refer to the HEATED OXYGEN SENSOR (HO2S) ACTIVATION REQUIREMENTS  and DRIVE CYCLE  articles for information on Heated Oxygen Sensor (HO2S) activation requirements and drive cycles

   No:  Proceed to the next step

2. A2: ELECTRICAL CHECK OF HEATED OXYGEN SENSOR(S) (HO2S) HEATER POWER SUPPLY 
   NOTE:

   • Refer to the Heated Oxygen Sensor (HO2S) location  article for information on Heated Oxygen Sensor (HO2S) locations
   • Complete the following electrical checks ONLY  on the sensor(s) with the related DTC(s) set
   1. Refer to the electrical circuit diagrams and check the heater power supply
   2. Switch ignition OFF
   3. Disconnect Heated Oxygen Sensor (HO2S) (with the related DTC(s) set)
   4. Switch ignition ON
   5. Pre catalyst oxygen sensor.  Measure the voltage between pin 4 and battery ground
   6. Mid and post catalyst oxygen sensor.  Measure the voltage between pin 1 and battery ground

   Is the measured voltage between 11 and 14 volts?

   Yes:  Proceed to the next step

   No:  Check for fuse failure

   Check connectors for signs of water ingress, and pins for damage and/or corrosion

   Check for vehicle harness failure - Wiring integrity short circuit to ground, short circuit to power, open circuit, high resistance

3. A3: ELECTRICAL CHECK OF HEATED OXYGEN SENSOR(S) (HO2S) HEATER RESISTANCE 

1. Refer to the electrical circuit diagrams and check the heater resistance
2. Switch ignition OFF
3. Make sure the Heated Oxygen Sensor (HO2S) connector is disconnected
4. Pre catalyst oxygen sensor.  Measure the resistance of the sensor between pin 4 and pin 3
5. Mid and post catalyst oxygen sensor.  Measure the resistance of the sensor between pin 1 and pin 2

Is the measured resistance between 1 and 15 Ohms?

Yes:  Check connectors for signs of water ingress, and pins for damage and/or corrosion

Check for vehicle harness failure - Wiring integrity short circuit to ground, short circuit to power, open circuit, high resistance

No:  Install a new Heated Oxygen Sensor (HO2S) component