Boost Pressure Sensor, Shorted To High Source - New Holland CX720 Repair Manual

0402.3-BOOST PRESSURE SENSOR, SHORTED TO HIGH SOURCE

(SERVICE TOOL FAULT CODE XXX) (B.30.A.95.81 - G.30.B.54)
CX860, CX880
0402.3 - BOOST PRESSURE SENSOR, SHORTED TO HIGH SOURCE (SERVICE TOOL FAULT CODE XXX)
Context:
Engine enabled - no restriction on fuel or speed
Cause:
Signal range outside threshold limits
Signal not plausible or intermittent fault
Possible failure modes:
1. Faulty sensor
2. Faulty connector or wiring
Solution:
1. Mechanical Fault
A. Inspect the tubing between turbocharger and inlet manIfold. Ensure that no leakage points exist and all
connections are tight.
B. If the tubing and connections are okay continue with step 2.
2. Harness connector fault
A. Inspect the harness connector onto the sensor. Ensure that the connector is not damaged, the pins are
correctly located in the connector body and that it is a tight fit onto the sensor.
B. If the harness connector is okay continue with step 3.
3. Sensor Fault
A. To test the sensor the voltage needs to be read between the output wire, pin 1 and the sensor ground, pin
3, of the connector. Using a suitable probe into the wire, the voltage should range from 0.9-1.1 V at 450
- 550 rpm , to 1.0-1.3 V at 2660 rpm . If there is voltage but out of range replace sensor, if Zero volts is
indicated continue with step 4.
B. The resistance of the wiring within the sensor can also be checked:
resistance between pins 1 and 2 = 3.3 kΩ
resistance between pins 2 and 3 = 2.5 kΩ
resistance between pins 1 and 3 = 2.5 kΩ
If the sensor is to specification continue with step 4.
4. Wiring faulty
A. Check the wiring from the engine ECU to the sensor connector. With the key start ON, +5 V should be
measured on pin 2 of sensor connector. If 0 volts is indicated check for an open circuit or short to ground
back to the engine ECU, connector X192, pin 23. Trace the fault and repair the wiring as required. If the
wiring to pin 2 is okay, continue with step B.
B. With the key start OFF, continuity to ground should be indicated on pin 3 of sensor connector. If no ground
is indicated, check for an open circuit back to the engine ECU, connector X192, pin17. Trace the fault and
repair the wiring as required. If wiring to pin 3 is okay, continue with step C.
C. With the key start ON, check pin 1 for a short to +12 V. If +12 V is indicated trace the fault and repair the
wiring to pin 1. If okay, check for an open circuit back to engine ECU, connector X193, pin 12. Check also
for a short to ground. If any fault is indicated trace and repair the wiring as required.
Series 1206 and above
POWER PRODUCTION - AIR INTAKE SYSTEM
2 4/7/2006
B.30.A / 23