Throttle Valve Control Module, Checking: Notes

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements 

• The 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 identified as Throttle Drive for Electronic Power Control -G186- located in the Throttle Valve Control Module - J338-. It is controlled by the Engine Control Module (ECM) -J623- with primary inputs from the Accelerator Pedal Position Sensor -G79- /Accelerator Pedal Position Sensor 2 -G185- and Throttle Drive Angle Sensor 1 and 2 -G187/G188- as well as other peripheral inputs.

The Throttle Valve Control Module -J338- contains the following components: 

• Throttle Drive for Electronic Power Control -G186-
• Throttle Drive Angle Sensor 1 for Electronic Power Control -G187-
• Throttle Drive Angle Sensor 2 for Electronic Power Control -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 accessible.

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

Checking voltage supply and wiring 

-- Switch the ignition On.

-- Using a Multimeter check the following wiring connections for voltage.

Throttle Valve Control Module -J338- electrical harness connector terminal	Measure To:
2 to 6	---
2	Ground (GND)

Specified value: about 5.0 V

-- Switch the ignition Off.

Continue test according to the following table: 

Value	Cause	Test
If the specified value was not obtained:	Open or shorted circuit	Checking wiring
If the specified value was obtained:	Check reference signal circuit	Checking Activation