Technical Description of OBD-II Trouble Code
The circuit for the ignition/distributor engine speed input is experiencing low voltage.
What does that mean?
This generic trouble code is applicable to all spark ignition engines, including certain Audi, Mazda, Mercedes, and VW vehicles.
The Powertrain Control Module (PCM) receives crankshaft position or timing information from the Crankshaft Position Sensor (CKP). This information is typically used to determine engine rpm.
The PCM also receives camshaft position or distributor timing information from the camshaft position sensor (CMP). When the voltage in either of these two circuits drops below a certain level, the PCM will set code P0322. This code indicates an electrical circuit fault.
The troubleshooting steps may vary depending on the manufacturer, type of ignition/distributor/engine speed sensor, and wire colors connected to the sensor.
Symptoms
The symptoms of a P0322 engine code may include:
Causes
The potential causes for this code to set are:
Diagnostic and Repair Procedures
A good starting point is always to check for technical service bulletins (TSB) specific to your vehicle. There may be a known issue with a known fix provided by the manufacturer, which can save time and money during diagnosis.
Next, locate the ignition/distributor/engine speed sensor on your vehicle. This may be a crank sensor/cam sensor, a pick-up coil/sensor inside the distributor, or a wire coming from the coil to the PCM to verify ignition system firing. Once located, visually inspect the connectors and wiring for any signs of scraping, rubbing, bare wires, burn spots, or melted plastic. Separate the connectors and carefully inspect the terminals inside for any signs of burning or corrosion. If cleaning of the terminals is necessary, use electrical contact cleaner and a plastic bristle brush. Allow the terminals to dry and apply electrical grease where they make contact.
Depending on the vehicle, poor connections or outdated ignition parts are the most likely cause for the P0322 code. Therefore, it is highly recommended to search for TSBs specific to your vehicle.
If you have a scan tool, clear the diagnostic trouble codes from memory and check if P0322 returns. If it does not, then the problem was most likely due to the connections.
If the P0322 code does return, further testing of the sensor and its associated circuits is necessary. The next steps will depend on the type of sensor you have: Hall Effect or Magnetic Pick up. You can usually determine the type of sensor by the number of wires connected to it. If there are 3 wires, it is a Hall Effect sensor. If there are 2 wires, it is a Magnetic Pick up style sensor.
If it is a Hall Effect sensor, disconnect the harnesses going to the Camshaft and Crankshaft Position Sensors. Use a Digital Volt Ohm Meter (DVOM) to test the 5V power supply circuit for each sensor to ensure it is receiving power (Red lead to the 5V power supply circuit, black lead to a good ground). If there is no 5 volts to the sensor, repair the wiring from the PCM to the sensor or consider a faulty PCM.
If the power supply circuit is functioning properly, use the DVOM to check if there is a 5V signal circuit for each sensor (Red lead to the sensor signal circuit, black lead to a good ground). If there is no 5 volts to the sensor, repair the wiring from the PCM to the sensor or consider a faulty PCM.
Next, check if there is a good ground at each sensor. Connect a test light to 12V and touch the other end of the test light to the ground circuit for each sensor. If the test light does not illuminate, there is a problem with the ground circuit. If the test light does illuminate, wiggle the wiring harness going to each sensor to check for an intermittent connection indicated by flickering of the test light.
If it is a Magnetic Pickup style sensor, you can test the sensor itself to determine if it is functioning properly. Test for: 1) Resistance 2) A/C voltage output 3) Short to ground
With the sensor disconnected, use an ohmmeter to measure the resistance between the 2 terminals of the Camshaft / Crankshaft Position Sensor. Compare the measured resistance to the specifications for your vehicle, typically ranging from 750 to 2000 ohms. While still on ohms, disconnect 1 lead of the ohmmeter from the sensor and connect it to a good ground on the vehicle. If you get any resistance reading other than infinite or OL, the sensor has an internal short to ground. Avoid touching the metal part of the leads with your fingers, as this may affect the readings.
Reconnect the leads of the DVOM to the 2 terminals of the Camshaft / Crankshaft Position Sensor. Set the meter to read A/C voltage. While cranking the engine, measure the A/C voltage output on the DVOM. Compare the measured voltage to the manufacturer’s specifications for your vehicle. Generally, a good rule of thumb is around 0.5V AC.
If all tests have passed so far and the P0322 code continues to appear, it is likely that the ignition/distributor/engine speed sensor has failed. However, the possibility of a failed PCM cannot be ruled out until the sensor has been replaced. In some cases, after replacing the sensor, it may need to be calibrated to the PCM for proper functioning.
If you are unsure, it is recommended to seek assistance from a trained automotive diagnostician. PCMs must be programmed or calibrated to the vehicle in order to be installed correctly.
