P1122 Engine Trouble Code
What is P1122?
P1122 indicates potential catalytic converter failure. If completely failed, your vehicle may not run properly and fuel economy will suffer significantly. Average replacement cost is $2,000–$2,140. This repair requires professional service and should not be delayed.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Code: | P1122 |
P1122 Symptoms
Check Engine Light
Illuminated dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration
Starting Problems
Difficulty starting the engine
P1122 Code Structure
Understanding what each digit means in the P1122 powertrain trouble code:
| P | 1 | 1 | 2 | 2 |
|---|---|---|---|---|
| Powertrain Code | Fuel And Air Metering | Fuel Rail/System Pressure — Too High | Turbocharger Boost Sensor A Circuit Low | Glow Plug/Heater Circuit 'A' Malfunction |
How to Fix P1122
Diagnostic Steps:
The catalytic converter has oxygen sensors before and after it. When warm and in closed-loop mode, the upstream O2 sensor reading should fluctuate, while downstream should remain steady.
Repair Solution:
Disconnected, dirty, or fouled spark plugs commonly prevent proper engine operation. Replace spark plugs every season or 25 hours. Verify proper spark plug gap. If plugs are good, check ignition components: spark plug wires, coils, and ignition module.
Technical Notes:
Parts or components should not be replaced based solely on P1122 DTC. Consult your vehicle service manual for proper diagnostic procedures, possible causes, and required testing before replacement.
P1122 Description
P1122 OBD-II Trouble Code: Throttle Position Sensor Circuit Intermittent Low Voltage is one of the definitions for the P1122; however your vehicles manufacturer may have a different definition for the P1122 code. Please check b
Main Cause
The primary reason for P1122 OBD-II Engine Trouble Code is: Fuel Rail/System Pressure — Too High.