Throttle Valve Control Module Checking

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements 

• The Engine Control Module (ECM) - J623- fuses OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position "P" or "N".
• A/C switched off.
• Ground connections between engine/transmission/chassis OK.
• Throttle valve must not be damaged or dirty.
• Coolant Temperature at least 80 °C.

Function 

Throttle valve operation occurs by an electric motor referred to as the Throttle Drive Motor -G186- located in the Throttle Valve Control Module - J338-. It is controlled by the Engine Control Module (ECM) -J623- with input from the Accelerator Pedal Position Sensor 1 -G79- /Accelerator Pedal Position Sensor 2 -G185- and throttle drive angle sensors.

The Throttle Valve Control Module -J338- is made up of the following components: 

• Throttle Drive Motor -G186-
• Throttle Drive Angle Sensor 1 -G187-
• Throttle Drive Angle Sensor 2 -G188-

The Throttle Valve Control Module -J338- cannot be serviced separately and must be serviced as a unit.

Test procedure 

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

Start diagnosis 

-- Connect the scan tool.

-- Switch ignition On.

-- Using the scan tool, check the throttle valve position (absolute) at idle stop:

Diagnostic text		Specified value
Throttle valve position (absolute)
Idle stop		3.0 to 25.0%

-- Slowly depress the accelerator pedal to Wide Open Throttle (WOT) stop while observing the percentage display. The percentage display must increase uniformly.

-- Using the scan tool, check the throttle valve position (absolute) at Wide Open Throttle (WOT) stop:

Diagnostic text		Specified value
Throttle valve position (absolute)
Wide Open Throttle (WOT) stop		84.0 to 97.0%

-- Switch ignition Off.

If the specified value was Not obtained: 

-- Remove the Throttle Valve Control Module -J338 - far enough so that the electrical connector terminals are reached.

-- Disconnect the Throttle Valve Control Module -J338- electrical harness connector -arrow-.

Checking resistance 

-- Using a multimeter, check the Throttle Drive (for Electronic Power Control (EPC)) -G186- at the Throttle Valve Control Module -J338- terminals 3 to 5 for resistance.

Specified value: 1.0 to 5.0 Ω (at 20° C)

If the specified value was Not obtained: 

-- Replace the Throttle Valve Control Module - J338.

If the specified value was obtained: 

-- Check the voltage supply of the Throttle Valve Control Module -J338- to the Engine Control Module (ECM) -J623-.

Checking voltage supply and wiring 

-- Switch the ignition On.

-- Using a multimeter, check the Throttle Valve Control Module -J338- electrical harness connector terminals 2 to 6 for voltage.

Specified value: at least 4.5 V

-- Switch the ignition Off.

If the specified value was Not obtained: 

Checking wiring 

-- Remove the Engine Control Module (ECM) -J623-.

-- Using a multimeter, check the Throttle Valve Control Module -J338- electrical harness connector terminals to the Engine Control Module (ECM) -J623- electrical harness connector T105 terminals for an open circuit. Refer to Wiring Diagrams.

Throttle Valve Control Module -J338- electrical harness connector terminals:	Engine Control Module (ECM) -J623- electrical connector T105 terminals:
1	34
2	54
3	91
4	55
5	90
6	56

Specified value: 1.5 Ω max.

If the specified value was Not obtained: 

-- Check the wiring for an open, high resistance or short to ground.

-- If necessary, repair the faulty wiring connection.

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

If no malfunction is detected in the wiring and if the voltage supply was Not OK: 

-- Replace the Engine Control Module (ECM) -J623-.

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 .