Applicable Systems
PC200 Excavator
Symptoms
Intake pressure sensor voltage below expected range; ECM may set boost-related derate.
Possible Causes
- Intake pressure sensor signal wire short to ground
- Sensor internal open circuit
- Sensor +5V supply missing
Troubleshooting Steps
- Step 1: Check sensor +5V supply at connector
+5.0V present at supply pin - Step 2: Check sensor signal wire for short to ground
No short to ground (resistance > 10k ohm) - Step 3: Replace sensor if internal fault suspected
New sensor signal voltage normal - Step 4: Verify sensor ground circuit continuity
Ground wire < 1 ohm to chassis - Step 5: Clear code and verify boost monitoring
Boost pressure reading accurate
How to Reset
Clear via service monitor after sensor replacement.
Common Replacement Parts
- Intake Air Pressure Sensor P/N: 621-06-16100
Frequently Asked Questions
- Q: Can CA122 and CA123 occur together?
No. CA122 means voltage too HIGH, CA123 means too LOW. If both appear in history, sensor was intermittent and should be replaced.
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Source: truckmanualshub.com Komatsu PDF
Category: Heavy Equipment
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