When your Komatsu excavator displays User Code E11 and Fault Code CA123, your machine is likely experiencing a significant drop in engine output. This code specifically points to a "Charge Air Pressure Sensor Low Fault," meaning the controller has detected an abnormally low signal from the pressure/temperature sensor circuit.
In this guide, we will break down the causes and the professional diagnostic steps required to get your machine back to full power.
1. Fault Code [CA123]: Charge Air Pressure Sensor Low Fault
|
User Code |
E11 |
Failure |
Charge Air Pressure Sensor Low Error |
|
Fault Code |
CA123 |
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|
Failure Details |
Low voltage detected in the pressure signal circuit of the boost pressure/temperature sensor. |
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|
Controller Response |
Fixes the charging pressure value and allows continued operation. | ||
|
Problem with the machine |
Engine power output drops. |
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Relevant Information |
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2. Troubleshooting
The following are possible causes and detection methods:
Issues with The Charge Pressure（Boost Pressure Sensor） Sensor Power Supply System
- Diagnosis method: If fault code [CA187] is displayed, perform fault diagnosis for [CA187] first.
Issues with the Boost Pressure/Temperature Sensor [Pressure Signal System]
- Diagnosis method: Turn the start switch to the OFF position, be prepared, and then turn the start switch to the ON position.
- Standard values:
| Boost Pressure & IMT | Voltage | |
| Between（3）-（1） | Power Supply | 4.75-5.25V |
- Note: If the voltage is abnormal, check the wire harness and controller as potential causes before making a judgment.
Short Circuit in The Wire Harness
- Diagnosis method: Turn the start switch to the OFF position, be prepared, and then perform the diagnosis without turning the start switch ON.
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Standard values:
Wiring harness
Resistance value
Between CE01(female)(44) - Boost Pressure & IMT(female)(4)
Min.100Ω
Short Circuit in Wire Harness (with Another Wire Harness)
- Diagnosis method: Turn the start switch to the OFF position, be prepared, and then perform the diagnosis without turning the start switch to the ON position.
- Standard values:
|
Wiring harness |
Resistance value |
|
Between CE01(female)(44) - Boost Pressure & IMT(female)(4) and between CE01(female)(47) - JC02- Boost Pressure & IMT(female)(1) |
Min.100Ω |
Issues with Wire Harness Connectors
The connecting components between the boost pressure/temperature sensor, engine wire harness, and engine controller may be faulty. Check these connecting components directly:
- Loose connectors, broken locks, or damaged seals.
- Corroded, bent, damaged, pushed-in, or swollen pins.
- Moisture or dirt in the connectors, or poor insulation in the connectors.
Faulty Engine Controller
- Diagnosis method: Turn the start switch to the OFF position, be prepared, then turn the start switch to the ON position to perform fault diagnosis.
- Standard values:
| CE01 | Voltage | |
| Between（37）-（47） | Power Supply | 4.75-5.25V |
3. More Technical Support
If you need more information or further assistance, please feel free to let us know via live chat or email: service@sinocmp.com. We will reach out to you ASAP.
Related to:
Error Code List for Komatsu PC200-8, PC220-8 and PC220LC-8 Excavators
How to Clear Fault Code DXA8KA on Komatsu PC200-8
