## Diesel Engine Management System

#### DTC Troubleshooting (cont'd)

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DTC P1236: Boost Pressure Control Negative Deviation

1. Check the ''On Board Diagnostic (OBD) System Check''.

Was the ''OBD System Check'' performed?

YES – Go to step 2.

NO – Go to OBD System Check.

1. Check the DTC.

Are there any other DTCs (beside DTC P1236) being output?

YES – Go to relevant DTC chart.

NO – Go to step 3.

1. Check for the following conditions:

- Damaged MAP sensor

- The vacuum hose work at the MAP sensor and EVRV (Turbo control) for leaks

Is a problem found?

YES – Repair as necessary.

NO – Go to step 4.

1. Check for the following conditions:

- Damaged Turboactuator valve or EVRV

- EVRV hose vacuum leaks

1. Visually and physically inspect the turboactuator pintle, for excessive deposits or any kind of a restriction.

If a problem is found, clean or replace turboactuator system components as necessary.

Is a problem found?

YES – Repair the turboactuator.

NO – Go to step 6.

1. Disconnect the EVRV connector.

1. Measure resistance between the EVRV 2P connector terminals No. 1 and No. 2.

Is there about 14.7 – 16.1 ohms (20°C (68°F)) (At room temperature)?

YES – Go to step 8.

NO – Replace the EVRV.

1. Remove the EVRV.

1. Connect the hand vacuum pump (with gauge) to the EVRV (A).

1. Apply 34 kPa (257 mmHg, 10 in. Hg) of vacuum with hand vacuum pump.

Were vacuum leaks found?

YES – Replace the EVRV.

NO – Substitute a known-good ECM and recheck. If symptom/indication goes away, replace the original ECM.

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