Thread: Car starts 3-4 seconds and shuts off. P0122 and P1122

DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage
DTC P1122 Throttle Position (TP) Sensor Circuit Intermittent Low Voltage

Car is Regal GS w/gen V N*

I put tog headers on the car, put all back together with both o2 sensors and now the car starts, runs 3-4 seconds and dies regardless of RPM. The security light does not come on but it was throwing the 1216(?? theft deterrent fuel shut off code) but at least no code from that anymore.

So far I've tried-

-Fuel Resistor Bypass
-Replace TPS w/spare I've checked ohm resistance on the TPS and its ranging 1-5 in steady increments when I move it, also tried replacing with a TPS from another N* I have sitting around and it threw the same code.
-Removed Theft Deterrent Fuel Shutoff ability, I was recieving the 1216(cant remember exact #) theft signal, but I disabled it with DHP tuner and the code is gone now.
-Fuel filter was replaced a months ago but fuel pressure seems good initially as I can rev the motor and RPM goes up just fine dies at 3-4 seconds limit.
-Checked 5vdc getting to the tps
-Inspected vac lines for possible leaks

I'm in the middle of checking the continuity from the TPS dk. blue wire to the PCM, but currently raining like hell every other five minutes so its been tough to get back out. Is the bogus Theft/Owner deterrent system still causing issues and just not throwing a code? Anyone have any ideas or suggestions that may have come across this before?

Continuity from TPS Dk blue to pinout #66 on PCM block appears good.

Generally when those TPS DTC's pop its from a disconnected TPS.

1.	Turn the ignition switch ON(II).

2.	Check the throttle position with the scan tool. Is there about 10% or 0.5 V when the throttle is fully closed and about 90% or 4.5 V when the throttle is fully opened?

Check voltage while wiggling the wires at the connector. It's common since it's directly over the exhaust.

0.6vdc when closed and 4.46vdc wide open. Tried with a second tps I have from another n* and read 0.55/4.46. Wiggling didnt drop voltage... Electrical problems are a nightmare

Unplug the maf, have tps connected and try that.

Now..I recently saw a post where tps was a problem and it was a common ground/fuse..

Tried with the MAF unplugged, same deal 3-4 seconds. I checked the ignition fuses in the engine bay, i'll check them in the kick panel now.

Sir

This the exact symptoms of the theft deterrent system disabling the fuel pump.
I know you "disabled" the code but the system may be shutting the fuel down - just not setting the code.
The TPS should not just turn the car off. I would expect it to stay running with a little pedal.

Bill, your continued support and time invested in help is greatly appreciated.

No fuses look blown, Tried to turn it over again after clearing the DTC's and its like the battery is dead already. Its probably only been 4 attempts to turn over and the battery has died. I have the headlights unplugged and nothing unnecessary is running. The battery currently reads 11.9vdc and wont turn, is this a sign of something else wrong?

Sir Rico,

Is there a way to manually disable the system manually? I went in and changed it through DHP so its no longer throwing the code, but if there is a fuse to pull or cat to skin i'll do it. I know there are bypass kits they sell on the internets but I'd like to avoid that.

Bill would know. I think you can solder a resistor somewhere in the return signal to the module.

But yes there is a way to bypass the entire module with the kit and may be same as above.

What year is the GS?

I have literally soldered a relay shut to keep it enabled to ensure pump couldn't turn off at all. Thing here is Rico might not realize. The injectors aren't injecting. I think the pump is able to pump...but the pcm won't inject. That's security. I'm off to look for that post.

Found some info about chaffed wires.

Chuck...can you post the FSM info about this code.

The GS is a 98. Here is what I saw from my recent scan:

Calibration Data>Security>Vehicle Theft Deterrent


VTD Is Disabled (1/stock=0(false)) true
VTD Auto Learn Timer (10/stock=600)
VTD Auto Learn Counter (1/stock=3)


I noticed there appears more which I have left stock:


Calibration Data>Diagnostics>Security


Ignore_Flash_Checksum (stock)
Disable_Flash_Security (stock)
Flash_Checksum (stock)


I can not find any other values that would relate to the security system, but I havn't touched the diagnostics part.

I think the second part of that needs to be changed. I did one...but don't have the info handy.

Here's a way to test. Pull the leads of a 194 (turn signal) bulb straight and put then into an injector connector. Have someone start the car while you watch that bulb for any flashes. If no flashes..then you aren't getting injector pulse. All you are getting is the cylinder prime. Which will happen when the security is pissed off.

my girlfriend had this problem with her 96 grand am gt and i searched forever until i found this three wire bundle in a wire harness in the little cabinet by the gas/brake pedals under the steering column, there are white, black, and yellow wires in the bundle. i cut the yellow wire and taped the ends off ever since then it hasnt had a problem starting

Bill
This is the only code I can think of or get info on that is fuel related to theft deterrent.

Reference: P1626-Theft Deterrent Fuel Enable Signal Not Received? - 3800Pro.com Forum

DTC P1626 Theft Deterrent Fuel Enable Signal Lost
Circuit Description
The Vehicle Theft Deterrent (VTD) system is incorporated within the body control module (BCM). The powertrain control module (PCM) monitors the state of health serial data message from the Theft Deterrent system to ensure that the PCM to BCM communications is established. If the PCM detects a loss of the state of health message while the engine is running, DTC P1626 will set. DTC P1626 can cause a no-start condition or normal operation depending on when the loss of Theft Deterrent system communication was detected. The engine will continue to start and run if the condition that set DTC P1626 occurred after the PCM received a valid theft deterrent password from the BCM and already allowed fuel during the ignition cycle. The engine will start and immediately stall if the condition that set DTC P1626 occurred before the PCM received a valid theft deterrent password. With this condition present, the PCM will inhibit fuel delivery and disable the starter until a valid theft deterrent password is detected. Refer to Content Theft Deterrent (CTD) Circuit Description .

Conditions for Running the DTC
The Theft Deterrent system has allowed fuel delivery.

Conditions for Setting the DTC
The PCM has detected a loss of the state of health serial data message from the Theft Deterrent system.

Action Taken When the DTC Sets
The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.

Conditions for Clearing the MIL/DTC
The DTC becomes history when the conditions for setting the DTC are no longer present.
The history DTC clears after 40 malfunction free warm-up cycles.
The PCM receives a clear code command from the scan tool.
Diagnostic Aids
For complete serial data line schematics and VTD system diagnosis, refer to Data Link Connector (DLC) Schematics in Data Link Communications and Vehicle Theft Deterrent (VTD) Operation in Vehicle Theft Deterrent.

An intermittent may be caused by:

• A poor connection

• Rubbed through wire insulation

• A wire broken inside the insulation

Check for the following conditions:

Important: Several BCM diagnostic procedures call for disconnecting the BCM and then turning the vehicle ignition to the RUN position. These procedures will result in the PCM setting DTC P1626. Therefore, DTC P1626 stored in history may be the result of previous BCM diagnostic work.


• Intermittent short circuit on the serial data circuit -- Refer to Data Link Communications Operation in Data Link Communications. Be sure to check all related wiring for an intermittent short to ground or short to voltage.

• Poor connection -- Inspect the PCM and BCM harness and connectors for:

- Improper mating

- Broken locks

- Improperly formed or damaged terminals

- Poor terminal to wire connection

• Damaged harness -- Inspect the wiring harness for damage. Check for an intermittent short or open circuit in the wiring harnesses related to the BCM, including the ignition, battery feed, ground, and Serial Data circuits.

Reviewing the Failure 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.

If the DTC cannot be duplicated and is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set. Also refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Step
Action
Values
Yes
No

1
Did you perform the Powertrain On Board Diagnostic (OBD) System Check?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check

2
Important: : If a loss of DLC data has already been diagnosed, clear this DTC and continue diagnosis with Powertrain On Board Diagnostic (OBD) System Check .


Is P1631, or UXXXX DTCs present?
--
Go to Diagnostic Trouble Code (DTC) List/Type
Go to Step 3

3
Important: : The replacement PCM must be programmed.


Replace the PCM. Refer to PCM Replacement/Programming .

Is the action complete?
--
Go to Step 4
--

4
Review and record the scan tool Failure Records data.
Clear DTCs.
Attempt to start the vehicle.
Does the vehicle start and continue to run?
--
Go to Step 2
--



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Document ID# 590153
2000 Buick Regal

So the car battery is charging, but I had a signal bulb laying around so its hooked up to the injector port.

I have also changed the settings and flashed the group i missed the first time. When its done charging I will crank it. Thanks for sticking with me.

Calibration Data>Diagnostics>Security


Ignore_Flash_Checksum (stock)
Disable_Flash_Security (255=disabled)
Flash_Checksum (stock)

Even after the new flash, the signal bulb hooked up to the injector feed wires did not light up.

I bought the car used and i found what looks like a plunger switch on the hood, I'm guessing previous owner had remote start and somewhere its not letting me start up. I traced the lines and one went and spliced into a dark purple line on the harness right in front of the front bank valve cover and the other split off and went through the firewall down by driver side pedals but had been cut clean off. I dont know if this is relevant as i pulled the system off and am still unable to start the vehicle. I may try to flash back to stock and just see what happens.

edit -

ran a continuity test on that dark purple wire the plunger switch was hooked up to, it runs to the ICM when it would be the 4th from the right looking at it.

Its working again.

I did the IT troubleshooting, reimage/reboot fixes everything.

I loaded a stock 01gs bin and the dtc 1626 came right on. Did the key reset for the standard 10min/10min/10min and it started right up. What is strange was before having the key/learn set to 1 time for 10 seconds on the previous bin, it did not work. Only after uploading the new/stock bin and doing the full 10min x 3 times did it work.

The theft system disables both the starter and the fuel. The behavior before I assume that I had successfully disabled the starter portion of the theft system but despite best efforts the fuel disable was still active or invisible.

Thanks to all who helped!