DIY PGMFI Diagnostics - Code 7 TPS

**ECU-MAN** · 21-05-2007 11:15 PM

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!

No part of this DIY is to be reproduced with out acknowledgment of the site and author it came from, ie me and ozhonda.com. Do not rip parts off and claim them as your own.

TPS Sensor, "Throttle Position Sensor" also known as TAS "Throttle Angle Sensor". The TPS is a variable resistor that measures the position of the opening of the throttle butterfly, and the rate at which the throttle is opened. The TPS is mounted on the side of the throttle body.

Aim:

Diagnose code 7

Required:

Basic Testing

- Digital Multi Meter
- paper clip

Symptoms

If your TPS is faulty you will suffer from flat spots and the MIL ( engine lamp ) will come on.

Basic Test

- Perform a Visual inspection and make sure the TPS sensor is Connected, make sure it does not have any physical damaged. ( common on imported motors )

TPS Sensor Pin out Picture

wire side of connector

**** Voltage Test ****

Set your multi meter to DC Volts ( 20v scale )

Step 1 ( Reference Voltage test )

Check the TPS sensor for its Reference Voltage from the ECU. Connect the Black Lead from your multi meter to the chassis for a good ground. Back probe* the TPS with the Red lead to Pin 3 of the TPS sensor while the sensor is connected.

KOEO* you must get 5v

If you get 5v proceed to step 2,

if you do not get 5v, repair open or short circuit to ECU from Pin 3 of TPS to the bellow ECU Pin ( also see continuity test bellow )

OBDO = C13
OBDI = C19
OBDIIa = D4
OBDIIb = C19

If you do not get 5v from the ECU pin above, replace the ECU.

STEP 2

Check TPS sensor for a good ground. Leave your Red lead from the above test on Pin 3 of the TPS. Back probe your Black lead into Pin 1 of the TPS.

KOEO* you must get 5v

If you get 5v proceed to step 3,

if you do not get 5v, repair open or short circuit to ECU from Pin 1 of TPS to the bellow ECU Pin ( also see continuity test bellow )

OBDO = C12
OBDI = C22
OBDIIa = D11
OBDIIb = C18

Leave your Black lead of the multi meter as is and move the Red Lead from Pin 1 of the TPS to the positive battery terminal. You should get 12v. If not, repair the wire between Pin 1 of the TPS and Pin listed above to the ECU

STEP 3 ( Do not start your engine for this test KOEO. key on engine off )

Check the TPS Signal. Connect the Black Lead from your multi meter to the chassis for a good ground. Back probe* the TPS with the Red lead to Pin 2 of the TPS sensor while the sensor is connected.

KOEO* at closed throttle you should get 0.45v to 0.5v
KOEO* at full throttle you should get 4.5v to 5.0v

if your signal voltage differs from the above by allot, go to STEP 4

as throttle position opens TPS voltage increases. As you open the throttle from closed throttle to full throttle, The voltage should increase with out jumping all over the place.

If you have access to a waveform viewer, then as you sweep the throttle open, you should get a nice clean line with out any glitches or drop outs.

If you do not get a signal on Pin 2, replace the TPS sensor with a known good one and retest. If you do get a signal at Pin 2, then check the signal at the ECU end.

OBDO = C7
OBDI = C11
OBDIIa = D1
OBDIIb = C27

If you get a good signal at Pin 2 of the TPS and no signal on the above ECU Pin, repair the Open circuit between the above ECU Pin and Pin 2 of the TPS.

replace the TPS if the output voltage jumps or glitches.

***** Its is always best to check sensor inputs at the ECU side *****

STEP 4

Adjust the TPS to correct value. The TPS is mounted to the throttle body with either two hex key bolts, or two rivet type bolts. The picture bellow shows hex bolt type of setup.

Start by loosening the two hex bolts in the pic above, that the yellow arrows are pointing to. If you have the flat type bolts. You wont be able to get a tool on the bolt. you will have to use a hacksaw blade to cut a flat on the bolts and then use a flat head screw driver on the bolt. This may result in removal of the throttle body. ( 2 nuts and 2 bolts. maybe a hose or two. This is beyond the scope of this DIY but easy to do. ).

anyway, with the TPS loose, you KOEO* and connect the Black Lead from your multi meter to the chassis for a good ground. Back probe* the TPS with the Red lead to Pin 2 of the TPS sensor while the sensor is connected. You will be able to rotate the TPS backwards or forwards. See pic bellow.

With the Throttle at closed throttle, set the TPS so the multi meter reads 0.45v, and then tighten up the TPS. Make sure you recheck the TPS voltage after you tighten the TPS.

**** Continuity Test ****

Set your multi meter to continuity. This setting is mostly a picture if a sound .))) when you touch the Red and Black leads together on your meter it should beep.

STEP 1

make sure the Ignition is off and unplug TPS Connector and the ECU Connectors for this test

Continuity test between TPS Pin 1 and ECU, Connect your Red multi meter lead on the TPS Pin 1, Back probe* the Black multi meter lead on the ECU Pin bellow that suits your car.

OBDO = C12
OBDI = C22
OBDIIa = D11
OBDIIb = C18

your multi meter should beep and read short or 000.0ohms. Place the black multi meter lead on a good ground source. You should not get beeping, this is testing for short to ground.

STEP 2

make sure the Ignition is off and unplug TPS Connector and the ECU Connectors for this test

Continuity test between TPS Pin 2 and ECU, Connect your Red multi meter lead on the TPS Pin 2, Back probe* the Black multi meter lead on the ECU Pin bellow that suits your car.

OBDO = C7
OBDI = C11
OBDIIa = D1
OBDIIb = C27

your multi meter should beep and read short or 000.0ohms. Place the black multi meter lead on a good ground source. You should not get beeping, this is testing for short to ground.

STEP 3

make sure the Ignition is off and unplug TPS Connector and the ECU Connectors for this test

Continuity test between TPS Pin 3 and ECU, Connect your Red multi meter lead on the TPS Pin 3, Back probe* the Black multi meter lead on the ECU Pin bellow that suits your car.

OBDO = C13
OBDI = C19
OBDIIa = D4
OBDIIb = C19

your multi meter should beep and read short or 000.0ohms. Place the black multi meter lead on a good ground source. You should not get beeping, this is testing for short to ground.

If any of your continuity tests fail between the TPS and ECU, repair the OPEN in the wire between the TPS and ECU that failed.

If any of your continuity tests fail between the TPS and ground, Find the short circuit and repair it. look for squashed wires, or for damage to any part of the PGMFI loom.

reset the ECU and road test the car.
* Notes

KOEO = Key On Engine Off

KOER = Key On Engine Running

Backprobe the sensor, use a paperclip and push it into the connector then touch/clip your multimeter lead to the paper clip

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!