[Quadragin]

Ok here is the situation: I working on a church member 98 catera, came to me crank no start, Thinking it was the pump I tested the fuel system by powering the fuel pump directly with a battery and connected pressure gauge directly to the output of the filter = 80psi and held pressure.
I then connected gauge to fuel rail and have steady 45psi, I also applied vacuum to the regulator and saw a change in pressure.
Cycling the key did not turn on the pump, so I jumper-ed the fuel pump relay and got power to the fuse and pressure in the rail tried to start but would not.
Pulled a plug and checked for spark on cyl #2 and have spark and 175psi compression, in swapping relays and fuses the symptoms has changed from crank no start to crank start and immediately dies.
Also The only way to get the car to have fuel pressure and run for a second is to cycle the key from the OFF position, If I go from run to start the pump does not run and the engine doesn't even try to start.
I have autoenginuity laptop software it shows the following codes: B1971, B1983, U1255, I also have an Innova scanner that only shows a P1503

 

[globuslive]

Ok here is the situation: I working on a church member 98 catera, came to me crank no start, Thinking it was the pump I tested the fuel system by powering the fuel pump directly with a battery and connected pressure gauge directly to the output of the filter = 80psi and held pressure.
I then connected gauge to fuel rail and have steady 45psi, I also applied vacuum to the regulator and saw a change in pressure.
Cycling the key did not turn on the pump, so I jumper-ed the fuel pump relay and got power to the fuse and pressure in the rail tried to start but would not.
Pulled a plug and checked for spark on cyl #2 and have spark and 175psi compression, in swapping relays and fuses the symptoms has changed from crank no start to crank start and immediately dies.
Also The only way to get the car to have fuel pressure and run for a second is to cycle the key from the OFF position, If I go from run to start the pump does not run and the engine doesn't even try to start.
I have autoenginuity laptop software it shows the following codes: B1971, B1983, U1255, I also have an Innova scanner that only shows a P1503

Any code starting with B is relates to body control module, in your case the code U1255, which usually belongs to module's communication codes, tells there is issue with data, coming in/out. Your pump most likely fine. I would look into wiring issues, oxidation or Connectors, or all together.
Catera's pump is engaged only when you crank, it's not typical gm car, which 99% of them would build the pressure with ignition cycle.
You either have Wrong key, or issue with security system, If it starts and dies instantly. If key is not programmed to the ECM, even tho it will turn ignition on, that's what you gonna get. Do you have security light on the dash on? Another B code you have points to the door lock, which I assume might be related to no start issue. When you unlock the driver door, it sends the signal to disarm factory alarm, and if that doesn't work properly, it might give you hard time. Try to open the lock with the key, interior lights should turn on when you do it. To me it sounds like alarm issue. Another thing is common is crank sensor, but you confirmed you have the spark, so it's less likely a problem with sensor. Good luck.


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[Quadragin]

Any code starting with B is relates to body control module, in your case the code U1255, which usually belongs to module's communication codes, tells there is issue with data, coming in/out. Your pump most likely fine. I would look into wiring issues, oxidation or Connectors, or all together.
Catera's pump is engaged only when you crank, it's not typical gm car, which 99% of them would build the pressure with ignition cycle.
You either have Wrong key, or issue with security system, If it starts and dies instantly. If key is not programmed to the ECM, even tho it will turn ignition on, that's what you gonna get. Do you have security light on the dash on? Another B code you have points to the door lock, which I assume might be related to no start issue. When you unlock the driver door, it sends the signal to disarm factory alarm, and if that doesn't work properly, it might give you hard time. Try to open the lock with the key, interior lights should turn on when you do it. To me it sounds like alarm issue. Another thing is common is crank sensor, but you confirmed you have the spark, so it's less likely a problem with sensor. Good luck.


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I no key fob just the key.
I opened the door pushed the lock button and closed. Security light came on steady and shut off after a bit.
Used the key to unlock and the interior lights came on. No security on or flashing. Tried to start same thing start and die.
Opened opened the door and closed security flashed until I put key in ignition and turned then it went off. no start
locked the door and waited for the Security light to go off, unlocked with key and the security light was flashing this time until i turn ignition.
Cleared the codes and tried the lock and unlock again, this time the security light stayed off again but no start and the P1503 came back.
This is the only key they have, sounds like the chip went bad??
tow to stealer for reprogram?

 

[globuslive]

Stealer might not even be able to, depends on their qualification level. It's not typical gm they know how to work on. Some probably never heard the model. I'll check the code later tonight

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[Quadragin]

Stealer might not even be able to, depends on their qualification level. It's not typical gm they know how to work on. Some probably never heard the model. I'll check the code later tonight

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A little more info, I tried the key relearn procedure = negitive.
I got an inline spark tester, and the only time the PCM sends spark signal is for those fir few revolutions then it goes dark. So Im thinking the Body Control Module took a dump

Thanks for your support

 

[globuslive]

A little more info, I tried the key relearn procedure = negitive.
I got an inline spark tester, and the only time the PCM sends spark signal is for those fir few revolutions then it goes dark. So Im thinking the Body Control Module took a dump

Possibly it's your crank sensor. Do it first. Body control module doesn't affect spark itself unless it's alarm related issue. It just won't let everything to work as it should. But it's common for catera to replace crank sensor, and you never gonna have a code for it. 30$ cost approximately. Book requires to wire it between oil lines, but it's really extra job for nothing, just find the place for new wire around where initial wiring goes, and you should be good. Just make sure it doesnt touch exhaust. But who knows if sensor doesn't work, than I would look into bcm.

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[Quadragin]

so the sensor is by the oil cooler lines under the motor? I have a lift so routing of the wire should not be an issue, it looks like an ABS sensor lol

 

[globuslive]

so the sensor is by the oil cooler lines under the motor? I have a lift so routing of the wire should not be an issue, it looks like an ABS sensor lol

Yes, near oil filter housing, 3 wires, and it has heating shield, kinda abs )

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