The P1220 trouble code is a manufacturer-specific powertrain code. Its exact definition depends entirely on the vehicle application, primarily indicating a series throttle control fault, a throttle position sensor 2 issue, or a timing control malfunction.
Because it is manufacturer-specific, the exact application must be verified. The code identifies a detected condition, and testing is required to identify the root cause before replacing any components.
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Key Takeaways
- P1220 is a manufacturer-specific code with definitions varying significantly between automakers.
- On Ford applications, it indicates a series throttle control system fault.
- On General Motors applications, it points to a throttle position sensor 2 circuit malfunction.
- On certain Toyota diesel applications, it indicates an injection timing control system fault.
- Proper diagnosis requires verifying the exact factory definition and testing the relevant circuits.
P1220 Code Description and Implications
The P1220 code is a manufacturer-specific powertrain definition. Because it is not a generic SAE code, its exact meaning depends entirely on the vehicle application.
Ford and Land Rover applications: P1220 indicates a series throttle control system fault. The control module detects an issue with the secondary throttle actuator or its control circuit, preventing proper airflow regulation.
General Motors applications: P1220 indicates a throttle position sensor 2 circuit malfunction. The powertrain control module detects an irregular voltage or signal from the second throttle position sensor inside the throttle body assembly.
Toyota diesel applications: P1220 indicates an injection timing control system malfunction. The engine control module detects an electrical fault in the timing control valve or spill valve circuit on the fuel injection pump.
Common Causes of the P1220 Code
Electrical faults, mechanical binding, and component degradation are the primary triggers, though the specific causes vary by manufacturer.
For Ford and Land Rover applications: The issue stems from a failed series throttle actuator motor, damaged wiring harnesses, carbon buildup binding the throttle plate, or a poor electrical connection at the module connector.
For GM applications: The fault is caused by a failed throttle position sensor 2, an open or shorted circuit in the throttle body wiring harness, or poor connections at the powertrain control module.
For Toyota diesel applications: The issue is caused by a failed timing control valve on the injection pump, damaged wiring to the spill valve, or a poor ground connection in the fuel system circuit.
Symptoms Associated With P1220
When the control module detects a fault in these specific monitoring systems, it illuminates the Check Engine Light.
Ford and Land Rover applications: You may experience reduced engine power, poor acceleration, or a limp-home mode if the secondary throttle system fails to operate correctly.
GM applications: You may experience a reduced engine power warning, rough idling, or stalling if the control module cannot verify the throttle plate position using both internal sensors.
Toyota diesel applications: You may experience severe power loss, rough running, or excessive smoke due to incorrect fuel injection timing caused by the timing control valve malfunction.
Diagnosing the P1220 Trouble Code
Accurate diagnosis begins by confirming the exact factory definition for your specific vehicle make and model.
Ford and Land Rover diagnosis: Inspect the series throttle body and actuator for carbon binding. Use a scan tool to command the secondary throttle and verify movement while checking the control circuit for opens or shorts.
GM diagnosis: Inspect the throttle body wiring for damage. Use a multimeter to measure the sensor reference voltage, signal return, and ground circuits for throttle position sensor 2 to identify electrical faults.
Toyota diesel diagnosis: Inspect the wiring to the injection pump timing control valve. Measure the resistance of the timing control valve solenoid and compare it to the manufacturer’s specification to verify its condition.
Repairing the P1220 Issue
Repairs must address the specific root cause identified during testing.
Ford and Land Rover repair: If the series throttle actuator fails testing or is bound by carbon, clean the assembly or replace the confirmed failed throttle body component. Repair any damaged wiring harnesses.
GM repair: If throttle position sensor 2 fails testing and the wiring is intact, replace the confirmed failed throttle body assembly. Repair any chafed wires and clear the codes to verify the repair.
Toyota diesel repair: If the timing control valve on the injection pump fails resistance testing, replace the confirmed failed valve. Repair any damaged wires in the spill valve circuit and verify proper injection timing.
Cost Considerations for P1220 Repairs
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Replacing a throttle position sensor or cleaning a throttle body is generally a straightforward repair with moderate costs. Replacing an integrated throttle body assembly or an injection pump timing control valve may require higher parts costs and specialized calibration.
Prevention Strategies for Future Occurrences
Inspecting throttle body assemblies and exposed wiring harnesses for early signs of carbon buildup, chafing, or degradation can help prevent mechanical binding and circuit faults.
Keeping electrical connectors clean and ensuring protective seals are intact may reduce moisture intrusion and prevent corrosion-related sensor or actuator faults.
Troubleshooting Tips and Best Practices
Do not immediately replace the engine control module just because a P1220 code is present. A failed sensor, a bound throttle plate, or a poor connection will produce the exact same fault reading.
Always verify the manufacturer-specific definition first. A code that means a series throttle fault on a Ford means a timing control valve issue on a Toyota diesel.
Check for Technical Service Bulletins for your specific vehicle. Manufacturers occasionally release updated throttle body part numbers or revised wiring harness routing procedures to address chronic circuit issues.
More OBD-II Codes
| P1219 | P1218 | P1217 | P1216 |
| P1215 | P1214 | P1221 | P1222 |
| P1223 | P1224 | P1225 | P1226 |
| P1227 | P1228 | P1231 | P1234 |
| P0121 | P0122 | P0123 | P0220 |
| P1512 | P1513 | P1546 | P1641 |
Frequently Asked Questions
Is P1220 a generic or manufacturer-specific code?
No. P1220 is a manufacturer-specific powertrain code. It indicates a series throttle control fault on Ford, a throttle position sensor 2 issue on GM, and a timing control fault on Toyota.
Can I drive my car with a P1220 code?
Driving is not recommended if the code indicates a throttle control failure or severe timing issue. Continued driving with reduced engine power or incorrect injection timing can cause further mechanical damage or unsafe driving conditions.
Will disconnecting the battery clear the P1220 code?
Disconnecting the battery may temporarily erase the code, but it will not repair a failed sensor, a bound throttle plate, or damaged wiring. The code will return once the monitor runs.
Can a dirty throttle body cause a P1220 code?
Yes, on applications monitoring a series throttle control system. Heavy carbon buildup can physically bind the secondary throttle plate, preventing the actuator from reaching its commanded position and triggering the circuit or performance fault.
Does P1220 always mean the throttle body is bad?
No. The code identifies a detected circuit or performance condition. This is frequently caused by damaged wiring, a poor connection, or a failed timing control valve. Components should only be replaced after testing confirms failure.
What Should You Do About the P1220 Code?
Confirm the exact factory definition for your vehicle, then follow the applicable manufacturer diagnostic procedure. Because P1220 is manufacturer-specific, the diagnostic path for a throttle control fault differs entirely from an injection timing issue.
Inspect the relevant system and components, including throttle actuators, position sensors, and timing control valves. Repair any confirmed wiring damage, or replace the relevant system components only after testing verifies the failure.
