DTC Troubleshooting: P1236 (172-3)

DTC P1236:  Boost Pressure Higher Than Expected

1.Turn the ignition switch ON (II).

2.Clear the DTC with the HDS.

3.Start the engine. Hold the engine speed at 2,000 rpm (min-1) without load (in neutral) until the radiator fan comes on, then let it idle.

4.Do the TURBOCHARGER BOOST TEST in the INSPECTION MENU with the HDS.

Is the result OK?


YES - Go to 5.


NO - Go to 7.


5.Test-drive under these conditions:
  • Engine coolant temperature above 80 °C (176 °F)
  • Engine speed more than 3,000 rpm (min-1)
  • Drive about 10 minutes

6.Monitor the OBD STATUS for DTC P1236 in the DTCs MENU with the HDS.

Does the screen indicate FAILED?


YES - Go to 7.


NO - If the screen indicates PASSED, intermittent failure, system is OK at this time. If the screen indicates NOT COMPLETED, go to 5 and recheck.


7.Turn the ignition switch OFF.

8.Check for a loose or damaged these turbo control vacuum line:
  • Vacuum pump and turbocharger boost control solenoid valve
  • Turbocharger boost control solenoid valve and turbocharger boost control diaphragm

Is the line OK?


YES - Go to 9.


NO - Repair or replace the damaged hoses, then go to 12.


9.Disconnect the vacuum hose (A) from the turbocharger boost control solenoid valve (B), and connect a vacuum pump/gauge (C) to the solenoid.

 

10.Turn the ignition switch ON (II), and apply vacuum to the hose.

Does the turbocharger boost control diaphragm operate?


YES - Replace the turbocharger boost control solenoid valve, then go to 12.


NO - Go to 11.

11.Replace the turbocharger assembly.

12.Reconnect all connectors and hoses.

13.Turn the ignition switch ON (II).

14.Reset the ECM with the HDS.

15.Start the engine. Hold the engine speed at 2,000 rpm (min-1) without load (in neutral) until the radiator fan comes on, then let it idle.

16.Test-drive under these conditions:
  • Engine coolant temperature above 80 °C (176 °F)
  • Engine speed more than 3,000 rpm (min-1)
  • Drive about 10 minutes

17.Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - If DTC P1236 is indicated, check for poor connections or loose terminals at the turbocharger boost control solenoid valve and the ECM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


NO - Go to 18.


18.Monitor the OBD STATUS for DTC P1236 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?


YES - Troubleshooting is complete.n


NO - If the screen indicates FAILED, check for poor connections or loose terminals at the turbocharger boost control solenoid valve and the ECM, then go to 1. If the screen indicates NOT COMPLETED, go to 15 and recheck.