B3000 2WD V6-3.0L OHV (1994)
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A single pulse indicates the entry mode. Then, observe the STO (self-test output) of the SST in the following:
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Using the SST,verify that the idle speed is within specification.
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A constant tone or self-test output (STO LO) readout indicates the idle speed is within specification.
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A beeping tone or STO LO readout at (1 Hz) indicates the idle speed is too slow.
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A beeping tone or STO LO readout at (4 Hz) indicates the idle speed is too fast.
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A beeping tone or STO LO readout at (8 Hz) indicates that the Throttle Position Sensor is out of range due to over-adjustment. Replace the
Throttle Position Sensor.
NOTE: Idle speed adjustment may be necessary after Throttle Position Sensor replacement.
CHECK RESULTS
Idle Speed Too Fast
1. Turn the ignition switch Off.
2. Remove the air intake hose from the throttle body.
View: Throttle Plate Orifice
3. Block the orifice in the throttle plate temporarily with tape.
NOTE: If the orifice already has a plug in it, perform steps (a) through (c). If the orifice does not have a plug then proceed with step 4.
(a) Perform the Key On Engine Off Inspection Procedure.
(b) If Diagnostic Trouble Code 121 is present adjust the throttle return screw, erase Diagnostic Trouble Codes and repeat steps a and b until
code is no longer present.
(c) If Diagnostic Trouble Code 121 is not present refer to the Diagnostic Index for other idle related symptoms.
See: Computers and Control Systems/Testing and Inspection/Symptom Related Diagnostic Procedures/Symptom Index
4. Install the air intake hose to the throttle body.
5. Start the engine and recheck the idle speed. If engine stalls, turn the air trim screw clockwise and repeat this step until engine idles.
6. If idle speed is still too fast, perform the following:
(a) Perform the Key On Engine Off Inspection Procedure.
(b) If Diagnostic Trouble Code 121 is present, adjust the throttle return screw, erase Diagnostic Trouble Codes and repeat steps (a) and (b)
until code is no longer present.
(c) If Diagnostic Trouble Code 121 is not present, remove tape blocking orifice in throttle plate and refer to the Diagnostic Index for other
possible causes.
7. If idle speed is OK now or slow, perform the following:
(a) remove the air intake hose from the throttle body.
(b) Remove the tape and install the proper plug from the service kit.
(c) Install the air intake hose to the throttle body.
(d) Start the engine and turn the throttle return screw clockwise until a constant tone or self-test output (STO LO) readout indicates the idle
speed is within specification.
Idle Speed Is Too Slow
1. Remove the air intake hose from the throttle body.
2. Verify the orifice in the throttle plate does not have a plug.
3. If the orifice has a plug, remove the plug and proceed with step 4.
4. Adjust the throttle return screw clockwise until a constant tone or self-test output (STO LO) readout indicates the idle speed is within
specification.
5. Disconnect the SST.
PROCEDURES FOR PLUG INSTALLATION
STEP 1
Remove air inlet tube(s) from throttle body.