Intake Manifold Tuning Valve, Checking

Special tools and workshop equipment required 

• multimeter.
• Wiring diagram.

Test requirements 

• Fuse -SB5- OK.
• The Engine Component Power Supply Relay -J757- OK.
• The parking brake engaged.
• The battery voltage at least 12.5 V.
• The selector lever of automatic transmission in position "P" or "N".
• All electrical consumers switched off (radiator fan must NOT run during test).
• A/C switched off.
• The fuel tank at least ¹ /₄ filled.
• The ignition switched off.

Test procedure 

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK .

Start diagnosis 

-- Disconnect the Intake Manifold Tuning (IMT) Valve -N156- electrical harness connector -1-.

Checking internal resistance 

-- Using a multimeter, check the Intake Manifold Tuning (IMT) Valve -N156- terminals 1 to 2 for resistance.

Specified value: 450 to 1000 Ω.

If the specified value was not obtained:

-- Replace the Intake Manifold Tuning (IMT) Valve -N156-.

If the specified value was obtained:

Checking voltage 

Crank the engine.

-- Using a multimeter, check the Intake Manifold Tuning (IMT) Valve -N156- electrical harness connector terminal 1 to ground (GND) for voltage.

Specified value: battery voltage.

-- Switch the ignition off.

If the specified value was not obtained:

-- Check the wiring from the Intake Manifold Tuning (IMT) Valve -N156- electrical harness connector terminal 1 to the Engine Component Power Supply Relay -J757- socket 8 for a short circuit to Ground (GND), or an open circuit.

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring:

Checking wiring 

If the manufacturers test box is being used, perform the following step.

-- Install the test box.

If the manufacturers test box is not being used, perform the following step.

-- Remove the Engine Control Module (ECM) -J623-. Refer to the appropriate service information.

-- Using a multimeter, check the Intake Manifold Tuning (IMT) Valve -N156- electrical harness connector terminal 2 to the Engine Control Module (ECM) -J623- electrical harness connector terminal T 60 for resistance.

Intake Manifold Tuning (IMT) Valve -N156- electrical harness connector terminal	Engine Control Module (ECM) -J623- electrical harness connector terminal or test box socket
2	52

Specified value: 1.5 Ω Max.

If the specification was not obtained:

-- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:

-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .

-- Perform a road test to verify repair.

If the DTC does not return:

Generate readiness code. Refer to READINESS CODE .

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:

-- Replace the Engine Control Module (ECM) -J623-. Refer to the appropriate service information.

-- Assembly is performed in the reverse of the removal.

Final procedures 

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .