Throttle Valve Control Module, Checking: Notes

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.

Test procedure 

-- Observe safety precautions. Refer to SAFETY PRECAUTIONS 

-- Observe Clean Working Conditions. Refer to CLEAN WORKING CONDITIONS 

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

Start diagnosis 

Function 

Throttle valve operation occurs by an electric motor in Throttle Valve Control Module - J338-. It is commanded by Engine Control Module (ECM) -J623- according to input from Throttle Position (TP) Sensor -G79- /Accelerator Pedal Position Sensor 2 -G185 - and related inputs.

Components of Throttle Valve Control Module -J338- :

• Throttle Drive for Electronic Power Control (EPC) -G186-
• Throttle Drive Angle Sensor 1 for Electronic Power Control (EPC) -G187-
• Throttle Drive Angle Sensor 2 for Electronic Power Control (EPC) -G188-

Function test 

-- 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 values are 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 Valve Control Module -J338- terminals 3 to 5 for resistance.

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

If the specification was Not obtained:

-- Replace the Throttle Valve Control Module - J338-. Refer to the Repair Information.

If the specification was obtained:

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