What does it mean?
This diagnostic trouble code (DTC) is a generic powertrain code, meaning it applies to all vehicles from 1996 onwards (Dodge, Chrysler, Hyundai, Jeep, Mazda, etc.). Although generic, specific repair steps may vary by make/model.
In my personal experience, I’ve found that a stored P0224 code means the Powertrain Control Module (PCM) has detected an intermittent malfunction in the Throttle Position Sensor (TPS) “B” circuit.
The TPS is typically a potentiometer-type sensor that completes a five-volt reference circuit. The TPS is mechanically actuated using an extension of the throttle plate shaft or a specially designed tab on the sensor. When the throttle is opened and closed, the contacts inside the sensor are dragged across a printed circuit board, varying the sensor’s resistance. As the sensor’s resistance changes, the TPS circuit voltage fluctuates. The PCM recognizes these fluctuations as varying degrees of throttle plate actuation.
The PCM uses the input voltage signals from the TPS to calculate fuel distribution and ignition timing. It also uses TPS input data to monitor intake airflow, exhaust oxygen content, Exhaust Gas Recirculation (EGR) function, and engine load percentage.
If the PCM detects a number of intermittent or erratic signals from the TPS over a defined period and under a set of programmed circumstances, a P0224 code will be stored and a Malfunction Indicator Lamp (MIL) may illuminate.
Severity and Symptoms
The TPS plays a significant role in engine operation; therefore, a stored P0224 code should be addressed with some degree of urgency.
Symptoms of a P0224 code may include:
Hesitation during acceleration
Black smoke from the engine exhaust (especially at startup)
Delayed engine starting (particularly during a cold start)
Reduced fuel efficiency
Related stored emission codes may accompany a P0224
Causes
Possible causes of this engine code include:
Faulty or improperly adjusted TPS
Open or shorted TPS “B” wiring or connectors
Binding or damaged throttle plate
Incorrect PCM or PCM programming error
Diagnostic and Repair Procedures
A good starting point is always to check the Technical Service Bulletins (TSBs) for your specific vehicle. Your issue might be a known problem with a published fix from the manufacturer, potentially saving time and money during diagnosis.
I typically use a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information (like ALLDATA DIY) to diagnose a P0224 code.
Successful diagnosis usually begins with a visual inspection of all wiring and connectors related to the system. I also like to test the throttle plate for signs of coking or carbon damage. Repair or replace any faulty wiring or components as needed, then recheck the throttle body and TPS.
Connect the scanner to the diagnostic connector; retrieve all stored trouble codes and note them for future reference. I also save any associated freeze frame data. My notes often prove useful if the stored code turns out to be intermittent. Then, I would clear the codes and test-drive the vehicle. Continue diagnosis if the code resets. If it doesn’t reset, the condition might need to worsen before a proper diagnosis can be made. Drive the vehicle normally until the PCM enters readiness mode or the code resets.
Proceed by checking the Technical Service Bulletins (TSBs) relevant to the specific malfunction (and vehicle) in question by consulting your vehicle information source. If applicable, use the information in the appropriate TSB to assist in your diagnosis. TSBs can be particularly helpful when diagnosing an intermittent condition.
The scanner’s data stream can provide useful information regarding faults and inconsistencies in the throttle position sensor. If you filter the scanner’s data stream to display only relevant data, you’ll get a more accurate response from the data.
If no issues are detected, use the DVOM to test the TPS. Using the DVOM gives you access to live data if the appropriate test leads are connected to the ground and signal circuits. Watch the DVOM screen while manually operating the throttle. Look for voltage spikes as the throttle is slowly actuated from the closed position to wide-open throttle. Voltage typically ranges from 0.5 volts at closed throttle to 4.5 volts at open throttle. If faults or other inconsistencies are detected, suspect that the tested sensor is faulty or improperly adjusted.
Additional Diagnostic Notes:
If the TPS has been replaced and a P0224 continues to be stored, consult the vehicle information source for TPS adjustment specifications
Use the DVOM (with test leads connected to the ground and signal circuits) to adjust the TPS accurately