Hey There,
Noob here to this community and looking for help. I have a 2007 Quest and I have recently had the Service and Engine and the VDC lights come on. When these lights come on together, I am not able to rev the van beyond 2000rpm. These light came on while I was driving the van home and was able to limp home not being able to go faster than 40km/hr. When I plug the code reader it gives me the codes of P2100 and P2101 codes, but I have just recently done the following work on it, replaced throttle body, replaced mass air flow sensor, replaced power steering pressure sensor. So I am not sure what is causing these lights to come on so randomly. It was problem free for a whole week and then this starts happening again. I am just at a loss with this one and looking for some help.
I appreciate any help or insight that I can get.
Thanks,
Mike
2007 Quest - SES & VDC Lights
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VStar650CL
- Technical Expert
- Posts: 8450
- Joined: Thu Nov 12, 2020 1:25 pm
- Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S
Re: 2007 Quest - SES & VDC Lights
Check the Throttle Control relay, try swapping it with another of the same type and see if the codes clear. If not, the TC supply runs through the ECM as an independent sub-circuit, you'll need to trace it end-to-end. It's possible the ECM itself is bad.
Re: 2007 Quest - SES & VDC Lights
Thanks for the reply. I did swap out the relay when I was replacing the throttle body to make sure that it wasn't the issue. So, I basically have to follow the wire to see if there are any breaks? Otherwise you're thinking it could be the ecm?VStar650CL wrote: ↑Mon Feb 01, 2021 8:17 amCheck the Throttle Control relay, try swapping it with another of the same type and see if the codes clear. If not, the TC supply runs through the ECM as an independent sub-circuit, you'll need to trace it end-to-end. It's possible the ECM itself is bad.
-
VStar650CL
- Technical Expert
- Posts: 8450
- Joined: Thu Nov 12, 2020 1:25 pm
- Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S
Re: 2007 Quest - SES & VDC Lights
You're most welcome. Even though it has a separate relay and doesn't depend on ECM power, the TC relay output still feeds into the ECM and then back out to the throttle body. The circuit carries relatively high current and the wiring generally makes a sharp, unsupported bend where it branches to the TB, so problems in the wires are not uncommon. A bad motor ground can cause the issue as well as power. Start by checking pin-fits at the relay, the ECM, and the TB, and also look for any "blackened" connector pins that indicate heating from high resistance. If that checks out, ohm the TB ground wire to the block, you should see very small milliohms. If that checks, back-probe the supply wire from the TC relay at the ECM end, there should be solid 12V power. Use a bulb-type test lamp to check, it's a power circuit and a bulb will validate that it can carry power. If that checks, ohm the output wire from the ECM to the TB and make sure it isn't open-circuit. If that also checks, back-probe the wire at the TB end and see if there's a changing "middle voltage" when the throttle is operated. If not, the ECM driver circuit is bad. It's not unusual for reman TB's to fail, so if all that checks out, try parts-warrantying the new TB before you condemn the ECM.
Re: 2007 Quest - SES & VDC Lights
This is a very helpful advice and I will start by having a look at the motor ground and power wires to make sure these aren't corroded or in bad shape. The TB I purchased was a new one or so I had thought and I actually had to replace the first one as my original issue was not resolved after replacing it but did get better once I installed the replacement, but anything is possible at this point. Once I go over the ground and power wires I will start on the next bit of suggestions to see if I can locate the problem that way.VStar650CL wrote: ↑Mon Feb 01, 2021 9:51 amYou're most welcome. Even though it has a separate relay and doesn't depend on ECM power, the TC relay output still feeds into the ECM and then back out to the throttle body. The circuit carries relatively high current and the wiring generally makes a sharp, unsupported bend where it branches to the TB, so problems in the wires are not uncommon. A bad motor ground can cause the issue as well as power. Start by checking pin-fits at the relay, the ECM, and the TB, and also look for any "blackened" connector pins that indicate heating from high resistance. If that checks out, ohm the TB ground wire to the block, you should see very small milliohms. If that checks, back-probe the supply wire from the TC relay at the ECM end, there should be solid 12V power. Use a bulb-type test lamp to check, it's a power circuit and a bulb will validate that it can carry power. If that checks, ohm the output wire from the ECM to the TB and make sure it isn't open-circuit. If that also checks, back-probe the wire at the TB end and see if there's a changing "middle voltage" when the throttle is operated. If not, the ECM driver circuit is bad. It's not unusual for reman TB's to fail, so if all that checks out, try parts-warrantying the new TB before you condemn the ECM.
Re: 2007 Quest - SES & VDC Lights
Me again, update on this as of 5 minutes ago. Just went out to try and start the van and it is now just cranking over and will not start. The codes that it is showing are P2100 and P2101. I haven't had time yet to try your suggestions from above but just wanted to provide more of an update on what is currently happening.VStar650CL wrote: ↑Mon Feb 01, 2021 9:51 amYou're most welcome. Even though it has a separate relay and doesn't depend on ECM power, the TC relay output still feeds into the ECM and then back out to the throttle body. The circuit carries relatively high current and the wiring generally makes a sharp, unsupported bend where it branches to the TB, so problems in the wires are not uncommon. A bad motor ground can cause the issue as well as power. Start by checking pin-fits at the relay, the ECM, and the TB, and also look for any "blackened" connector pins that indicate heating from high resistance. If that checks out, ohm the TB ground wire to the block, you should see very small milliohms. If that checks, back-probe the supply wire from the TC relay at the ECM end, there should be solid 12V power. Use a bulb-type test lamp to check, it's a power circuit and a bulb will validate that it can carry power. If that checks, ohm the output wire from the ECM to the TB and make sure it isn't open-circuit. If that also checks, back-probe the wire at the TB end and see if there's a changing "middle voltage" when the throttle is operated. If not, the ECM driver circuit is bad. It's not unusual for reman TB's to fail, so if all that checks out, try parts-warrantying the new TB before you condemn the ECM.
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