No Spark?

Hi,

When you say there is no power to the fuel pump relay, is there power to the fuse which supplies it? See pic 1. If not, let me know if any of the fuses in pic 2 have power.

Joe

Yes the fuel pump fuse has power. Or I mean, it lights up when I put the test light to it.

I got power to all the other fuses, just not that one. The fuel pump relay has no power. I was just on another site (which I will not name) that makes you pay for their "experts" and the gentleman told me I needed a new fuse box. Needless to say after I replaced the fuse box (today) I'm having the same problem. I'm sure it's something that I don't know about, like a connection that I'm not thinking of...

Hi,

No, you're not missing anything. Take a look at the pic below. I need to confirm that there is power to the fuse indicated. Next, the dark green wire with a white tracer is from the PCM. That is what energizes the relay to power the pump. You need to check if it is getting power. If it is, last is the gray wire that sends power to the pump. Check it for power.

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Next, here is a diagnostic flow chart for diagnosing electrical issues related to the fuel pump. Pictures 2 and 3 are the actual steps. I don't know if you are comfortable doing this, but I wanted to add it.

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2006 Buick Truck Rendezvous FWD V6-3.5L VIN L
Fuel Pump Electrical Circuit Diagnosis
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pump Testing and Inspection Component Tests and General Diagnostics Fuel Pump Electrical Circuit Diagnosis
FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS
FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS

CIRCUIT DESCRIPTION
When the ignition is turned ON, the powertrain control module (PCM) turns ON the fuel pump relay, which turns ON the in-tank fuel pump. The in-tank fuel pump remains ON as long as the engine is cranking or running and the PCM is receiving reference pulses. If there are no reference pulses, the PCM turns the in-tank fuel pump OFF 2 seconds after the ignition is turned ON or 2 seconds after the PCM no longer receives reference pulses.

DIAGNOSTIC AIDS
- Inspect the ground connection for the fuel pump. Ensure all ground connections are clean and tight.
- The following conditions may have caused the fuel pump fuse to open:
- The fuse is faulty.
- There is an intermittent short in the fuel pump power feed circuit.
- The fuel pump has an intermittent internal problem.
- For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections. See: Vehicle > Component Tests and General Diagnostics

TEST DESCRIPTION

Step 1 - Step 14

See pic 2


Step 15 - Step 27

See pic 3


The numbers below refer to the step numbers on the diagnostic table.
3. This step determines if the condition is located on the coil side or the switch side of the circuit.
4. This step verifies that the PCM is providing voltage to the fuel pump relay.
5. This step tests for an open in the ground circuit to the fuel pump relay.
6. This step determines if a voltage is constantly being applied to the fuel pump relay.
13. This step determines if the condition with the circuit is intermittent. If the fuse does not open, inspect the supply voltage circuit between the fuse and the fuel pump for an intermittent condition.

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Let me know if this helps or what you find.

Joe

First of all, before I get into the pictures that you've sent, I just want to say thank you because you've already helped me more than the guy on the other site. All he keeps saying is, "I can give a diagram for that fuel pump and fuse box. I'm starting to wonder if this guy is even an expert...

You are very welcome. I'll try my best to help. Wiring issues can be a bit tricky simply because they can occur anywhere in the system. I have actually had the wire break under the insulation. You can't tell it is broken until you actually touch the specific spot. So, lets give this a try and see if we can figure it out together.

Take care,
Joe

Getting ready to work on my car. can I use the test light to probe the (green) wire for the PCM to see if it gets power or do I have to check at the end? I'm new to this mechanic thing but I'm learning.

You can, but I believe it sends a 5v reference signal, so the light may be dim.

Let me know.
Joe

Okay, so no power to the PCM.

I'm starting to think that's the problem.

I also have no power to the PCM relay or both fuses..I took it apart and cleaned it (it was very dirty), the PCM that is, and checked the connections. They all looked fine. I cleaned the wires and sprayed the connectors with connector cleaner and still no power. I'm thinking the PCM has gone bad. I'm going to get a better code reader later.

Hi,

When you checked for power at the fuse, did you have the key in the run position? Did you check both sides of the fuse? If there is no power there, we have to look further into the issue. The PCM sends the signal to the relay, which energizes it, thus allowing the power from the pump fuse to power the pump.

Let me know how you checked the fuel pump fuse and if it is the exact same way it was originally. Also, I realize you cleaned and inspected items. Did you check the connections at the fuse box?

Let me know.
Joe

So I check in both on and off positions. The fuel pump fuse (10A) works. The relay gets no power. The connections at the fuel pump are fine. I changed the fuse box the other day. The connections at the PCM are fine. The PCM relay fuse and PCM sensor fuse do not have any power to them. Neither does the PCM relay. So what I'm saying is, the PCM is getting no power at the fuse box. The green and white wire also has no power. I recall you telling me to check that as well...

Is it the under hood fuse box that was replaced? Are the three fuses in the attached pic good and have power to them?

Let me know. If they are not getting power and you replaced the fuse box, it doesn't make sense. Is the replacement fuse box new or used?

Joe

Okay so, I'm not at my car right now, but I will go check in the morning. To answer the questions, yes I changed the under hood fuse box (as per the "expert") on the other site. Once I changed it, I had the same issue; no power to the fuel pump and no lights. The guy told me the fuse box had the exact same issue as the last one. The fuse box is used. It was from a 2005 Buick Rendezvous Ultra with 123,989 miles on it. The engine was a 3.6 so the fuse boxes matched. Now the IGN 1 and ignition fuse both get power. I'll check the other one.

Let me know what you find.

Joe

Okay, so I got power to all three fuses.

Okay, if the fuses are good, I need you to check power to pin 19 in the harness to the PCM. See attached pic. If there is power there, connect the PCM and check for power out from pin 37. If there is no power, then it's related to the PCM. If there is no power to pin 19, you have an open circuit between the ignition 1 fuse and the PCM.

Let me know.

Joe

Okay, so let's go back a little bit. Something didn't sit right with me about the fuses I checked the other night so I brought my shop light with me and it turns out I checked the wrong fuse when you asked me to check the ignition fuse and relay. Turns out, I have no power to the ignition main fuse.

Hi,

If you aren't getting power to the 60 amp ignition fuse, something is wrong with the fuse box. The power comes direct from the battery into the box and then is fused (60 amp) to other things. So, power is being lost between the battery and the fuse. Take a look at the pic I attached. It shows one power supply from the battery introduces power to multiple fuses. The ignition 1, 60 amp fuse is one of them. Do the other fuses around the Ignition 1 fuse have power?

Let me know.
Joe

Sorry about that, I guess I said the wrong thing, I'm not getting power to the ignition fuse. The (15A) one. I have included the picture of my actual fuse box with the correct fuse that is not getting power. I hope that helps...

The fuse box is shaped differently that what I show in the manual. However, if that fuse isn't getting power, are the ones around it?

I don't know if you ever replaced a breaker in the electrical box at your home, but the same principal applies. You have a steel power bar that always has power. When you put the breaker in the box, it contacts that bar and then you can control the power to different circuits in the house based on amperage. The same idea with the fuse box in the car. That box has a connector that has power from the battery at all times. The fuse takes the power from that supply and transfers it to another pin for a specific circuit. If the fuses near it have power, it should as well.

Let me know. I hope my analogy made sense. I'm really trying here. LOL

Joe

So are you trying to ask me to check the other fuses around it? So here's how I can answer your question: when I check my test light to see if I have a good ground I usually test the side of the fuse box (positive cable), and the three fuses (empty slots) next to the ignition, cruise, and vent. Not sure if you're asking to check to see if the harness is getting power or not? Wait. I just got it. I finally understand. Let me try this: are you asking if I'm getting power to connector C1? I've included a picture. So I got no power to 27 but I have power to 28. Hope that helps...

Hi,

Yep, you got it. Now this is what doesn't make sense. If you have power to 28 and not 27, there has to be either a pin pushed in, a wire not making contact, or the box is bad (which at this point doesn't make sense to me).

Joe

PS: I'm sorry to make this so confusing. It is much easier when the part is in front of me. LOL

Yeah, wouldn't make sense to me either, so I'm going to try to do a more in depth check on this. I haven't been able to do too much because I'm doing a water pump on an Acura (a whole headache), but I will be able to do more tomorrow. I just know there is something I'm not getting correct. I wonder if the wires going to the connector are messed up somehow.. however, I checked that pink wire and the green/white wire the other day and got no power to both of them. Now here's a theory, would I have these problems if the connector isn't pushed in all the way?

Also you're not confusing at all. I'm the one that's confusing I'm sure. There is something that I'm not getting. that's for sure.

You are not at all confusing. We are both learning together at this point simply because it isn't making sense to either of us. If the pins are pushed out, then the fuse may not be making a connection and completing the circuit. Is that what you mean? If so, yes, that is very possible.

Joe

Bear with me here, I've ordered a already programmed pcm from Flagship one. I believe that's the problem.

Hi,

No problem. I hope that takes care of the issues. Let me know.

Hope all is well,
Joe

I surely will. Until then I'll keep checking wires.

Yes I'm going to keep you guys updated mainly because I really appreciate the help, and I would like to help anyone else who encounters this situation. This site has helped me tremendously.

Okay, so I got a whole bunch of questions.. now I just got a new scanner today and got to use my new toy, it's called the ThinkDiag. pretty good scanner (even though I have no idea what these numbers mean. So I looked up my security status (because a mechanic suggested it might be security) and I got this...(picture included) help please!

I also have found this likely issue...

The second code you provided indicates the PCM is bad. Take a look at the attached pic. It is the diagnostics for this code (B1009). I feel bad saying this, but contact the local Buick dealer and see if you can purchase just the eeprom. Either way, the eeprom or PCM will require programming.

I wish I had better news.

Let me know if you have other questions or if I can help.

Joe

Yeah, I kind of figured that a while ago. There were too many problems. When I did the scan it said I had a code P0481 for a bad cooling fan number 2 and 3. Plus the fact that things kept going out one after another. Now what is this EEPROM you speak of? Remember I ordered a new computer like two weeks ago. However after reading lots of BBB complaints, I doubt I'll be getting that unit anytime soon.

Hi,

You look like a young man in your picture attached, so the easiest thing to compare it to is the RAM memory in your computer. EEPROM stands for electronically erasable programmable read only memory. In your vehicle, it is a permanent memory that is physically part of the control module. The EEPROM contains program and calibration information that the power-train control module (PCM) needs in order to control the powertrain operation.

Special equipment, as well as the correct program and calibration for the vehicle, are required in order to reprogram the control module.

I have to be honest, I'm not sure if the EEPROM is even available for your vehicle separately.

I hope that makes sense.

Joe

Well I've ordered a new PCM that's scheduled to be here Wednesday. Hopefully that will be the answer.

Please let us know what you find. We are interested to see what it is.

Okay. so, here's the deal:Changed the PCM lights come on now. Still no start. No fuel pump at all. Think diag says the fuel system is still disabled. There is an issue with my security system that I can't seem to fix. It's right under my nose.. there's a gentleman named Mike eyecanfixthat on YouTube that had a very interesting video on a 2006 Buick. He said the guy changed the PCM multiple times and has the same issue.. he hooked it up to a computer and now disabled the anti theft.. wondering how I can do that.

When you crank the car over is the security light flashing? if so this guide will help you reset it:

https://www.2carpros.com/articles/how-to-reset-a-security-system

Please run down this guide and report back.