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Discussion Starter · #1 ·
The error code on my 1988 Acura Legend indicated my Throttle Position sensor was bad. I replaced it 2 years ago from a wrecking yard. I wasn't planning on keeping the car long since I rarely use it now, So I bought another one from the yard and it is supposed to be good. Better than paying nearly $600 for a new one at the dealer. Anyway, I was looking over mine to get started and noticed a few things. A loose wire - fixed that. Then !!! the top hose on the throttle body is disconnected. I thought a simple matter of just following the curvature and finding where it goes. I can't find it! It looks like some sort of vacuum hose but I can't find it. Can anyone help? I went to the dealer and they said its too old that they don't have any info on it ! What! Anyone help please. I have a picture of what I am talking about but don't know how to post it here.
 

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Disconnected vacuum hose could just be causing the code 7: throttle angle, go to the online manual, sticky'd; "Auto Zone - G1 Engine Diagrams" thread by sciachir, lots of useful tips and informations.

You'll find the throttle body/throttle position sensor under "Fuel System", also vacuum schematics under "Driveability & Emissions"... hope this helps and good luck :)
 

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Throttle Positioning sensor

My transmission is starting to do strange things like shift down when I am trying to pick up speed, this happens periodically when I am in drive then it will just kick in and return to normal. Someone said they thought it could be the throttle positioning sensor, what are the symptoms? how do I know if that is what is wrong?
 

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Hkolody said:
My transmission is starting to do strange things like shift down when I am trying to pick up speed, this happens periodically when I am in drive then it will just kick in and return to normal. Someone said they thought it could be the throttle positioning sensor, what are the symptoms? how do I know if that is what is wrong?
Your probably reffering to the throttle pressure; kind of pressure that results when engine vacuum changes. Low vacuum, due to an open throttle or heavy load, results in high throttle pressure. High throttle pressure will tell the shift valve to move into a lower gear position.

It's also possible that your auto tranny is doing this due to a kickdown valve malfunction, simply check the cable or linkage for proper adjustments, hope this help answer your question... good luck!
 

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Discussion Starter · #7 ·
pnoye2 said:
Disconnected vacuum hose could just be causing the code 7: throttle angle, go to the online manual, sticky'd; "Auto Zone - G1 Engine Diagrams" thread by sciachir, lots of useful tips and informations.

You'll find the throttle body/throttle position sensor under "Fuel System", also vacuum schematics under "Driveability & Emissions"... hope this helps and good luck :)
Thanks for the tip on the diagrams. I found it once but lost the link. I just tried it again. I searched for 'sciachir' and found his reference. But when I link and cut and paste to autozone, it comes back, "page not found". Do you have the link? Thanks
 

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i know the 89-90 auto trans does'nt use vacuum for the t.v.
we have a cable that goes down to the transmission.....i wonder if this has ever gone out on our cars before...
 

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The throttle angle sensor is mounted on and driven by the throttle body unit. The sensor
is a variable resistor (potentiometer) that is used by the ECU to detect throttle movement
and position. A 5 volt reference signal is applied from ECU pin C13 and a ground signal
on pin C14. When the throttle is opened the sensor resistance changes which is read as a
varying voltage signal at pin C7. At idle position the sensor voltage is approx. 0.5V and

approx. 4.5 V at full throttle.







Code 7 indicates a malfunction in the throttle angle sensor or sensor circuit.

NOTE: This test requires the use of Acura sensor test harness part no.
07GMJ-ML80100 or equivalent. Wire colors referenced in testing procedures refer to
test harness coloring and not the actual harness wire color.

1. Remove Alternator Sense fuse in underhood relay box for 10 seconds to reset
ECU.
2. Start engine and observe diagnostic LED.

Flashes code 7 , proceed to step 4.
Does not flash , proceed to next step.

3. Malfunction is intermittent. Check connections between ECU and throttle angle
sensor. End of test.
4. Turn ignition off.

Image Throttle Angle Sensor Diagnosis



5. Connect sensor test harness between throttle angle sensor and harness
connector.
6. Turn ignition on and check voltage between RED and GRN test harness
terminals.

Approx. 5 volts , proceed to step 13.
Not approx. 5 volts , proceed to next step.

7. Measure voltage between RED terminal and ground.

Approx. 5 volts , proceed to next step.
Not approx. 5 volts , proceed to step 9.

8. Repair open in GRN/WHT wire between throttle angle sensor and ECU terminal
C14. End of test.
9. Turn ignition off.
10. Install test harness between ECU and harness connector. If test harness is not
available, carefully backprobe wires at ECU connector.

Image Throttle Angle Sensor Code 7 Diagnosis


11. Turn ignition on.
12. Check for voltage between ECU terminals C13 and C14.

Approx. 5 volts , proceed to next step.
Not approx. 5 volts , replace electronic control unit. End of test.
13. Measure voltage between GRN and WHT wires with throttle full open.

Approx. 4 volts , proceed to step 15.

Not approx. 4 volts , proceed to next step.

14. Check for short in RED/YEL wire between ECU terminal C7 and throttle angle
sensor. If wire checks OK, replace throttle angle sensor. End of test.
15. Turn ignition off.
16. Install test harness between ECU and harness connector. If test harness is not
available, carefully backprobe wires at ECU connector.
17. Turn ignition on.

Image Electronic Control Unit Pin And Connector Identification


18. Check voltage between ECU terminals C7 and C14.

Approx. 4 volts , replace electronic control unit. End of test.
Not approx. 4 volts , proceed to next step.

19. Repair open RED/YEL wire between ECU terminal C7 and throttle angle sensor.
 

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Discussion Starter · #12 ·
Great info. Thank you. I remember reading somewhere but couldn't remember. Thanks for the post. One more question, can I make that harness? I have connectors, wires, etc.... but need a guide as to what the harness looks like. Any help here?
Thanks again.
 

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Discussion Starter · #13 ·
Thanks jmm67 . I checked around to get the harness, but the response is that they don't have it? Do you know where to get the test harness? Or what does it look like? Can I make it from an old harness from an Acura from a salvage yard?
 

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Discussion Starter · #15 ·
Are the wire colors on the Test harness the same as on the connectors. I can't find a test harness anywhere. The dealers have no idea what Im talking about. I can make my own if I find the right mating connectors. I think I can back probe the ECU? Any suggestions?
 

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ok man, im sorry its come down to this ... all that test harness is ... ford had one called a test out box, its a set of pins that corrisponds to pins on the computer and harness so you dont have to back probe wires. In essance your checking for a short/open/ or high resistance in the wires. From the sounds of things ... if you car has never been in a wreak and hasnt been driven into the salt water, the harness is fine and it may be a common ground ... altho this may not be. Has anyone hacked up your harness? have you tried another throttle position sensor? it is possible that it may have gone bad. You can check this part but its hard to do with a regular digital mulitmeter you would pick up from downtown parts store. You need a graphing volt ohm meter which do cost a pretty penny ... thank god i got one. You can check it ... its difficult to do tho.
 

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Discussion Starter · #17 ·
Thanks for the advice on a graphing Multimeter. I can get one from work. Saves a bunch of $ that way. As for the harness. I asked about the diagram only because the instructions I have that state the color to probe refers to the test harness not the wire of the car's harness. So I was confused.
A bit of good news and I have to thank this forum for the help. Someone suggested cleaning it inside with some cleaners. I took apart the boot to the Throttle assembly. I reached into the Throttle sensor with an electrical cleaner that won't harm plastic and sprayed. I let it set and then started the car again. It gave the same engine code. Repeated it a few times along with using carb cleaner to clean up the TB itself. It wasn't that dirty but cleaned it anyway. At this point I figured I have nothing to lose so also sprayed the inside of sensor with the carb cleaner since I had a replacement Assembly I found in a Salvage yard parts place. I waited to check mine because I didn't know if this salvaged part was good. I tried the car again and it did the same thing. I let it go til after Christmas. I started it after Xmas and Its good now. All I can guess is that the cleaners cleaned up the sensor by sitting or its intermittent problem. Either case, I thank you guys here at this forum. And it runs. It was my daughter's car so I didn't really know how fast this car is. Man, it ran like a bat out of h****. Wish it wasn't so expensive to upkeep.
Anyway, getting long winded. Id still like the wiring schematic or advice on it so I can make one up. I had this problem before and paid someone to replaced the throttle body assembly with one I found in a yard 2 years ago. I would like to be able to diagnose it before working on it next time.
 

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Discussion Starter · #18 ·
Does anyone know a good way to insure that my 88 Legend will pass smog? After this throttle body problem, I really want a smooth smog check. I'm changing the oil and new air cleaner to start. Should I run a light weight oil like 5-20w for smog? What's recommended in these cars? I live in the Riverside/San Diego area. Anyone recommend a good smog shop to pass it without too much trouble? Should I run a pretest first? Any recommendations? It's Ca of course and what a nightmare state for smog.
 
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