Engine General Information and Diagnosis: 1A-45
Troubleshooting for 1.DEF: Pressure too low
Check the boost pressure sensor connections.
Check the connections of the boost pressure control solenoid valve.
Check the ECM connections.
Repair if necessary.
Check the sealing of the high pressure air circuit:
• Disconnected or pierced pipes.
• Pressure sensor disconnected or poorly fitted (seal present).
• Intercooler pierced (to check the intercooler: with the vehicle stationary, stabiles the engine speed between
3500 to 4000 rpm and check there are no leaks).
Check the conformity of the turbocharging pressure signal and perform Test 5 and 6 of Fault Finding-Tests
referring to “Test 5: Variable geometry turbocharger control” and “Test 6: Rotating part of a turbocharger”.
Check that the turbocharger and its control circuit are working:
• With the engine switched OFF, make sure the control rod is in the resting position.
• Start the engine and make sure that the control rod operates to the high stop. (when the engine stops, the
control rod must return to the resting position).
If the control shaft does not move correctly, carry out the following checks:
1. Vacuum pressure command check:
a. Disconnect the solenoid valve intake hose and connect it to a vacuum pressure gauge.
b. Start the engine and stabilise it at idle speed.
If the vacuum pressure does not reach 70 – 90 kPa (0.7 – 0.9 kg/cm
2
, 9.9 – 12.8 psi): check the vacuum
pressure circuit from the vacuum pump.
c. Stop the engine, reconnect the inlet hoses and go to Step 2.
2. Solenoid valve control check:
a. Disconnect the solenoid valve outlet hose.
b. Start the engine and stabilise it at idle speed.
c. Place your hand on the solenoid valve and block the outlet connection with your thumb.
If there is no detectable vibration of the solenoid valve, check that the ECM output is working correctly
(Refer to “DTC P0033: Turbo Charger Bypass Valve Control Circuit Malfunction” 1.DEF).
3. Solenoid valve functioning check:
a. Attach the pressure gauge to the solenoid valve outlet connection.
b. Start the engine and stabilise it at idle speed.
c. If the vacuum pressure does not reach 70 – 90 kPa (0.7 – 0.9 kg/cm
2
, 9.9 – 12.8 psi), replace the boost
pressure control solenoid valve.