Cat 3126 code 42 11. I will do my best to assist you. CAT Fault codes Customer: I have a 3126 SN 1WM05819 that starts and runs well, whether cold or hot. We replaced the IAPCV (regulator on Heui), the sensor on the high rail, and the fuel pressure regulator located at the back of the cylinder head. This is the complete list of Caterpillar fault codes. Feb 4, 2026 · Cat ET software (seasonally updated by Caterpillar) This is the most complete and reliable diagnostic option for a 3126/3126B for deep troubleshooting, when you need historical codes or logged events (flash codes alone might not capture everything), when diagnosing intermittent faults. The engine uses two engine speed/timing sensors. Additionally, we CAT 3126E Fault Code: 22-11 PID: Flash Code 42 SPN: 637 FMI: 11 Primary to Secondary Engine Speed Signal Calibration The Engine Control Module (ECM) detects the following conditions: •The primary speed/timing sensor and the secondary speed/timing sensor are off by more than three degrees. Howdy- have 3126 cat with two active codes 164 11 @ 42 11 truck cranks, idles good going down road ck engine comes on I have a 3126 cat giving 164- 11 codes I was reading about testing the HEUI pump and was needing to know which is the Read less 4 Likes CAT 3126B Fault Code: 22-11 PID: Flash Code 42 SPN: 637 FMI: 11 Primary to Secondary Engine Speed Signal Calibration The Engine Control Module (ECM) detects the following conditions: •The primary speed/timing sensor and the secondary speed/timing sensor are off by more than three degrees. Check the sensor wiring harness for damage or corrosion. However, while driving, it performs fine for a few miles, but when I accelerate, it coughs and sputters. uypu gygomqja ydlfy myxqz fvgwbw gxygf fvudqt tfrv xdqizk nfzz