What Does P1220 Mean?
P1220 indicates a malfunction in the Series Throttle Control System. This code applies to vehicles with a dual-throttle or series-throttle setup where a secondary throttle body works in conjunction with the primary throttle for traction control or emissions management. The ECM has detected that the secondary throttle is not responding correctly to commands.
Common Causes
25%
Failed secondary throttle body actuator motor
25%
Faulty secondary throttle position sensor providing incorrect feedback
20%
Carbon buildup on the secondary throttle blade causing binding or sticking
15%
Wiring or connector issue in the secondary throttle control circuit
15%
ECM control module fault or calibration error for series throttle logic
Diagnostic Steps
1
Use a scan tool to monitor the secondary throttle commanded position vs. actual position. A significant deviation confirms the malfunction.
2
Visually inspect the secondary throttle body for carbon buildup, sticking, or mechanical binding. Clean with throttle body cleaner if deposits are found.
3
Check the secondary throttle actuator motor by measuring resistance and commanding it through its range with a scan tool bidirectional control.
4
Inspect the secondary throttle position sensor output voltage through its full range for dead spots, dropouts, or out-of-range readings.
5
Test the wiring and connectors between the ECM and the secondary throttle assembly for continuity, insulation, and proper pin fit.
6
If the throttle body, motor, and wiring all test good, check for ECM software updates or recalibrate the throttle control system per manufacturer procedures.
Estimated Repair Cost
$200 - $900
Parts + labor, varies by vehicle and location
P1220 indicates a malfunction in the Series Throttle Control System. This code applies to vehicles with a dual-throttle or series-throttle setup where a secondary throttle body works in conjunction with the primary throttle for traction control or emissions management. The ECM has detected that the ...
The most common cause of P1220 (Series Throttle Control System Malfunction) is: Failed secondary throttle body actuator motor
Typical repair costs for P1220 range from $200 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A malfunctioning series throttle can cause unexpected power reduction, surging, or hesitation during acceleration. The vehicle may enter limp mode limiting speed. Loss of throttle control accuracy is a safety-critical concern during highway driving.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1220 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Electronic Throttle Control System
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
