Code No. P1299: Variable Geometry Turbocharger Control System Malfunction (low pressure)

FUNCTION

The engine-ECU controls the duty ratio of the variable geometry control solenoid valve so that the actual boost pressure can become the target boost pressure.

TROUBLE JUDGMENT

Check Condition

Engine is running

Judgment Criterion

Actual boost pressure is lower than target boost pressure by less than 6.7 kPa

FAIL-SAFE AND BACKUP FUNCTION

The throttle valve is opened (Electrical discontinuity).
The EGR control is stopped (fully closed).
The DPF regeneration is prohibited.
The fuel injection amount is restricted (Output restriction).
The open angle of the accelerator pedal is restricted.
The turbocharger control is prohibited.
The AS&G control is prohibited.

PROBABLE CAUSES

Failed variable geometry turbocharger control system
Failed engine-ECU

DIAGNOSTIC PROCEDURE

STEP 1. Check on intercooler air hose.

Check whether the hose between turbocharger and inlet manifold is disconnected or damaged.

Q. Is the check result normal?

	Go to Step 2.

	Repair.

STEP 2. Check on vacuum hose of manifold absolute pressure sensor.

Check whether the vacuum hose of manifold absolute pressure sensor is disconnected or damaged.

Q. Is the check result normal?

	Go to Step 3.

	Repair.

STEP 3. Check turbocharger supercharging pressure.

Check turbocharger supercharging pressure (Refer to GROUP 15 - On-vehicle Service - Turbocharger Supercharging Pressure Check ).

Q. Is the check result normal?

	Go to Step 4.

	Repair.

STEP 4. Check on clogged intercooler.

note

When checking the clogged intercooler, make a visual check or use an air blower.

Check whether the intercooler is being clogged or not.

Q. Is the check result normal?

	Go to Step 5.

	Replace the intercooler.

STEP 5. Check on clogged EGR cooler.

note

When checking the clogged EGR cooler, make a visual check or use an air blower.

Check whether the EGR cooler is being clogged or not.

Q. Is the check result normal?

	Go to Step 6.

	Replace the EGR cooler.

STEP 6. Check on clogged EGR pipe (A, B).

Check whether the EGR pipe (A, B) is being clogged or not.

Q. Is the check result normal?

	Go to Step 7.

	Replace the EGR pipe (A, B).

STEP 7. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the check result normal?

	Replace the engine-ECU.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).