HELP !! My check engine light just came on

[goatherder]

Ok my check engine light just came on. A week and a half ago I changed my thermostat. My X was over heating and that fixed that. Just thought i'd mention that. Now the check engine light is on so I stoped by the local garage and had them put a computer on it to check the error codes, this is what it read:

PO 122
TP Sensor low
P1 000 OBD cycle

The only one I think I know is the Throttle Position Sensor Low, maybe. I don't know to much about these things. I hope someone can help. Any help would be greatly appriciated. Thanks Guy

 

[Robert]

The P1000 code just means that you haven't completed all of the OBD-II readiness tests yet since your battery was last disconnected or your PCM was cleared. It takes 2-3 days of driving it with a minimum of 8 hours to cool off back down to ambient conditions to complete all of the readiness checks. Give it a couple of days without disconnecting your battery or doing a PCM reset and your P1000 will clear. As far as the TPS error, if you are sure you didn't bump it and loosen it up a bit, it might be time to replace it.

 

[dogfriend]

description from 97 Powertrain Manual

P0122: ATTEMPT TO GENERATE THE OPPOSITE THROTTLE POSITION ANGLE (VOLTAGE) PID READING

Diagnostic Trouble Code (DTC) P0122 indicates the TP sensor signal is less than the Self-Test minimum value of 3.43% (0.17 volts).

NOTE:
Throttle Position Sensor A (TP-A) is the same as Throttle Position (TP) Sensor.

NOTE:
An intermittent fault can cause a Continuous Memory DTC P0122. If a Continuous Memory DTC P0122 is still present after DH11 through DH14, go to «DH20».

Possible causes:

-- Damaged TP sensor.

-- TP not seated properly (tightened down).

-- Open TP SIG or VREF harness.

-- TP SIG harness short to SIG RTN or PWR GND.

-- Damaged PCM.

l Key off.

l Disconnect TP sensor. Inspect for damaged or pushed out pins, corrosion and loose wires. Service as necessary.

l Leave TP sensor disconnected.

l Jumper VREF circuit to TP circuit at the TP sensor vehicle harness connector.

l Key on, engine off.

l NOTE:
If any Scan Tool communication concern exists, remove jumper and go to «DH14».

Access TP PID (TP V PID) with the Scan Tool.

l Is the TP PID (TP V PID) greater than 92.27% (4.60 volts)?

Yes
TP SIG shorted to SIG RTN in TP sensor, or TP SIG or VREF open in TP sensor. REPLACE TP sensor. REMOVE jumper. RECONNECT all components. RERUN «Quick Test».

No
VREF or TP SIG open in harness or PCM, or TP SIG shorted to SIG RTN (or PWR GND) in harness or PCM. REMOVE jumper. GO to «DH12».



I would check your wiring going to the TPS for damage / corrosion. It could be the TPS or wiring going to the TPS.

 

[goatherder]

Wow! Thanks guys for the great info. Looks like we're getting far beyond my limited mechanical abilities. I guess im going to have to take it to the shop to be fixed. Hope it won't cost to much. They charge about 90 bucks an hour around here.

Thanks again, any other help would be greatly appriciated.

 

[dogfriend]

It shouldn't take them too long to diagnose it, because it is either the TPS itself, the PCM (not very likely) or the wiring between them.

Definately check to make sure it is plugged in and the wiring looks ok, you may save your self a few $ that way

Good luck

 

[goatherder]

Ok, so if my TPS was loose and I plugged it back in(which it was and which I did) will the check engine light go off or do I need to diconnect the battery to let the computer reset its self? I want to thank everyone who has written in to help, this sure is a great site.

 

[dogfriend]

If you disconnect the battery for a few minutes (10-15) it should reset the stored codes. It may take as much as 50 miles of driving for the truck to relearn proper idle settings, etc. Some codes will clear themselves after a certain number of starts without seeing the problem reoccur, but I don't know if this code is one of them.

If you disconnect, you will get the P1000 code until you have driven a certain number of cycles as Robert pointed out earlier.

 

[goatherder]

Ok, thanks again for all the help im going to go disconnect my battery and see if the check engine light comes back or if the loose connector was the problem.