TPS Question

[NOS2006]

Well, I posted a week or so back about a clicking/whining type noise coming from my car's engine compartment. Took everything apart, put it back together and we've got the same problem, except it starts now (it wasn't starting before, but we figured that separate problem out). I've now got the P0122 code for TPS low voltage. When testing the TPS with a multimeter, on the one setting (1.5V) but no other settings there is a clicking noise coming from #2 in this diagram:



We took #2 off (I don't know what sensor this is) and did the same "test" over again and found that there is a click because the sensor thing retracts a little (it's spring loaded) when the terminals are touched.

Originally, my dad had thought the clicking noise we heard was coming from the throttle body. So, what exactly is my problem? What is #2 in that diagram? And why (also, is this good or bad) would that retract when touching the terminals?

Thanks for the help in advance, everybody.

[BLLDOGG]

Re: TPS Question

What year and everything?

i looked on SI and found that the TPS for a 98' should vary from below 1volt to about 4v at WOT. let me try to find that sensor

[BLLDOGG]

Re: TPS Question

(1) Fuel Pressure Regulator
(2) Idle Air Control (IAC) Valve
(3) Throttle Position (TP) Sensor
(4) Engine Coolant Temperature (ECT) Sensor
(5) Camshaft Position (CMP) Sensor
(6) EVAP Canister Purge Solenoid Valve
(7) Heated Oxygen Sensor (HO2S) Bank2 Sensor1
(8) Fuel Injectors
(9) Manifold Absolute Pressure (MAP) Sensor
(10) Positive Crankcase Ventilation (PCV) Valve

same pictures as your i found.

[NOS2006]

Re: TPS Question

1998 Camaro 3.8 A4.

[BLLDOGG]

Re: TPS Question

let me know if you need a schematic.

DTC P0112 Intake Air Temperature (IAT) Sensor Circuit Low Voltage




Circuit Description
The Intake Air Temperature (IAT) sensor is a thermistor which measures the temperature of the air entering the engine. The PCM applies 5 volts through a pull-up resistor to the IAT sensor. When the intake air is cold, the sensor resistance is high and the PCM will monitor a high signal voltage on the IAT signal circuit. If the intake air is warm, the sensor resistance is lower causing the PCM to monitor a lower voltage. DTC P0112 will set when the PCM detects an excessively low signal voltage on the intake air temperature sensor signal circuit.

Conditions for Setting the DTC
• No ECT sensor, MAF sensor, or VSS DTCs present

• The engine has been running for over 10 seconds.

• Vehicle speed is greater than 40 km/h (25 mph).

• IAT signal voltage indicates an intake air temperature greater than 135°C (275°F).

• The above conditions are present for at least 20 seconds.

Action Taken When the DTC Sets
• The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed.

• The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

Conditions for Clearing the MIL/DTC
• The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.

• The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

• The DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.

Diagnostic Aids
Check for the following conditions:

• Poor connection at the PCM - Inspect harness connectors for the following conditions:

- Backed out terminals.

- Improper mating.

- Broken locks.

- Improperly formed or damaged terminals.

- Poor terminal to wire connection.

• Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the IAT display on the scan tool while moving connectors and wiring harnesses related to the IAT sensor. A change in the IAT display will indicate the location of the malfunction.

• Skewed or mis-scaled IAT Sensor. Refer to Temperature vs Resistance table.

If DTC P0112 cannot be duplicated, the information included in the Fail Records data can be useful in determining vehicle mileage since the DTC was last set.

Test Description
Number(s) below refer to the Step number(s) on the Diagnostic Table:

Verifies that the fault is present

If DTC P0112 can be repeated only by duplicating the Fail Records conditions, refer to the Temperature Vs. Resistance Values Table. The table may be used to test the IAT sensor at various temperatures to evaluate the possibility of a shifted sensor that may be shorted above or below a certain temperature. If this is the case, replace the IAT sensor.

If the IAT sensor appears to be OK, the fault is intermittent; refer to Diagnostic Aids.

This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

DTC P0112 IAT Sensor Circuit Low Voltage Step
Action
Value(s)
Yes
No

1
Was the Powertrain On-Board Diagnostic (OBD) System Check performed?
--
yes, Go to Step 2
no, Go to the Powertrain On Board Diagnostic (OBD) System Check

2
Turn ON the ignition switch.
Observe the Intake Air Temp display on the scan tool.
Is Intake Air Temp. greater than specified value?
130°C (266°F)
yes, Go to Step 4
no, Go to Step 3

3
Turn ON the ignition switch.
Review and record scan tool Fail Records data.
Operate the vehicle within Fail Records conditions as noted.
Using a scan tool, monitor Specific DTC info for DTC P0112.
Does the scan tool indicate DTC P0112 failed this ign?
--
yes, Go to Step 4
no, Go to Diagnostic Aids

4
Disconnect the IAT Sensor electrical connector.
Observe Intake Air Temperature on scan tool.
Is Intake Air Temperature less than the specified value?
-38°C (-36°F)
yes, Go to Step 6
no, Go to Step 5

5
Turn OFF the ignition switch
Disconnect the PCM electrical connectors.
Check the IAT sensor signal circuit for a short to ground.
Is the IAT sensor signal circuit shorted to ground?
--
yes, Go to Step 7
no, Go to Step 8

6
Replace the IAT Sensor. Refer to Intake Air Temperature (IAT) Sensor Replacement .

Is action complete?
--
yes, Go to Step 9
--

7
Repair the IAT sensor signal circuit. Refer to Wiring Repairs .

Is action complete?
--
yes, Go to Step 9
--

8
Replace the PCM.


Important:
The replacement PCM must be programmed. Refer to PCM Replacement/Programming .


Is action complete?
--
yes, Go to Step 9
--

9
Turn ON the ignition switch.
Review and record scan tool Fail Records data.
Clear DTCs.
Operate the vehicle within Fail Records conditions as noted.
Using a scan tool, monitor Specific DTC info for DTC P0112.
Does the scan tool indicate DTC P0112 failed this ign?
--
yes, Go to Step 2
System OK

[NOS2006]

Re: TPS Question

Okay, <1V-4V@WOT. I'm not too good with multimeters and really don't know much about 'em. :(

[BLLDOGG]

Re: TPS Question

Let me know if you need a schematic


Idle Air Control (IAC) System Diagnosis




Circuit Description
The PCM controls engine idle speed by adjusting the position of the Idle Air Control (IAC) motor pintle. The IAC is a bi-directional motor driven by two coils. The PCM pulses current to the IAC coils in steps (counts) to extend the IAC pintle into a passage in the throttle body to decrease air flow. The PCM reverses the current pulses to retract the pintle, increasing air flow. This method allows highly accurate control of idle speed and quick response to changes in engine load.

Diagnostic Aids
Check for the following conditions:

Poor connection at PCM or IAC motor. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
Damaged harness. Inspect the wiring harness for damage.
Restricted air intake system. Check for a possible collapsed air intake duct, restricted air filter element, or foreign objects blocking the air intake system.
Throttle body. Check for objects blocking the IAC passage or throttle bore, excessive deposits in the IAC passage and on the IAC pintle, and excessive deposits in the throttle bore and on the throttle plate. Check for a sticking throttle plate. Also inspect the IAC passage for deposits or objects which will not allow the IAC pintle to fully extend.
Vacuum leak. Check for a condition that causes a vacuum leak, such as disconnected or damaged hoses, leaks at EGR valve and EGR pipe to intake manifold, leaks at throttle body, faulty or incorrectly installed PCV valve, leaks at intake manifold brake booster hose disconnected, etc.
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.

This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed. Refer to PCM Replacement and Programming Procedures in Powertrain Control Module (PCM) and Sensors.

Step
Action
Value(s)
Yes
No

1
Was the On-Board Diagnostic (OBD) System Check performed?
--
yes, Go to Step 2
no, Go to the Powertrain On Board Diagnostic (OBD) System Check

2
Start engine.
All accessories OFF (A/C, Rear defroster etc.)
Using a scan tool, command RPM up to 1500, down to 650, and then up to 1500 while monitoring Engine Speed on the scan tool.
Does Engine Speed remain within 50 RPM of the RPM commanded?
--
yes, System OK
no, Go to Step 3

3
Disconnect the IAC.
Install J 37027-A IAC System Monitor.
With the engine running, command RPM up to 1500, down to 650, and then up to 1500 while observing the IAC System Monitor node lights.
Does each node light cycle red and green (never OFF)?
--
yes, Go to Step 5
no, Go to Step 4

4
Check the following circuits for an open, short to voltage, or short to ground:
- IAC A Low.

- IAC A High.

- IAC B Low.

- IAC B High.

If a problem is found, repair as necessary. Refer to Wiring Repairs .
Was a problem found?
--
yes, Go to Step 12
no, Go to Step 10

5
Was a low idle symptom or rich condition noticed?
--
yes, Go to Step 6
no, Go to Step 7

6
Visually/physically inspect for the following conditions:

• Throttle body tampering (throttle lever stop screw turned).

• Restricted air intake system.

• Check for a possible collapsed air intake duct, restricted air filter element, or foreign objects blocking the air intake system.

• Throttle body. Check for objects blocking the IAC passage or throttle bore, excessive deposits in the IAC passage and on the IAC pintle, and excessive deposits in the throttle bore and on the throttle plate.

Was a problem found?
--
yes, Refer to appropriate section for on-vehicle service
no, Go to Step 8

7
Visually/physically inspect for the following conditions:

• Vacuum leaks.

• Throttle body tampering (throttle lever stop screw turned).

• Throttle plate or throttle shaft binding.

• Accelerator and cruise Control cables for being misadjusted or for binding.

• Faulty, missing, or incorrectly installed PCV valve.

Was a problem found?
--
yes, Refer to appropriate section for on-vehicle service
no, Go to Step 8

8
Check for a poor connection at the IAC harness connector.
If a problem is found, replace faulty terminals as necessary. Refer to Wiring Repairs .
Was a problem found?
--
yes, Go to Step 12
no, Go to Step 9

9
Replace IAC valve. Refer to Idle Air Control (IAC) Valve Replacement .

Is the action complete?
--
yes, Go to Step 12
--

10
Check for a poor connection at the PCM harness connector.
If a problem is found, replace faulty terminals as necessary. Refer to Wiring Repairs .
Was a problem found?
--
yes, Go to Step 12
no, Go to Step 11

11
Replace the PCM.

Important: The replacement PCM must be programmed. Refer to PCM Replacement/Programming


Is action complete?
--
yes, Go to Step 12
--

12
Clear DTCs.
Start engine.
All accessories OFF (A/C, Rear defroster etc.)
Using a scan tool, command RPM up to 1500, down to 650, and then up to 1500 while monitoring Engine Speed on the scan tool.
Does Engine Speed remain within 50 RPM of the RPM commanded?
--
yes, System OK
no, Go to Step 3

[NOS2006]

Re: TPS Question

Thank you sir.

[NOS2006]

Re: TPS Question

lol Well I replaced the TPS and my dad ended up breaking the IAC valve why playing around with it this morning while I was in work.. so he's going to replace it. I personally think the IAC is what's wrong, anyway because it's making a REALLY loud noise when the car is running.

Strange part, is I have to press the accelerator slightly to start it and it'll die after running around 30-60 seconds after starting. That could be the IAC's fault, I think..

[NOS2006]

Re: TPS Question

Replaced the IAC and now the car will idle without stalling out...
There's a loud clicking sound that sounds like it's coming from the throttle body.. That's with a new TPS and IAC Valve. Ideas?