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3rd & 4th Generation (19921996 & 19972001) Toyota Camry Discussion for years: 1992-1996 & 1997-2001 Topics of discussion range from fuel economy, safety, modifications, performance all involving America's favorite family car, the Toyota Camry.

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Old 11-18-2012, 09:17 PM   #1 (permalink)
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COR Relay

Hello,
1997 Camry 2.2, 208,000 mi. After tons of troubleshooting, I have no power to the COR relay. I am suffering from no power to the fuel pump.
To be technical, I am getting no power to the G-R wire that feeds the COR relay. I found the wire at the ECU. I disconnected the harness and checked the continuity of the G-R wire from the ECU to the COR relay. Checks good.
I replaced the ECU with 2 other ones, so I don't think it is the ECU. I checked the ignition switch, all continuity tests checked good at the switch. Even though there is a post 1 at the ign. sw. the harness does not support it with a wire. Therefore any continuity checks that involved post 1 showed erratic, all others were fine.
Any thoughts?
Thanks,
Henry

Last edited by gejettest; 11-18-2012 at 09:18 PM.
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Old 11-19-2012, 06:39 AM   #2 (permalink)
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When checking for power on the G-R wire, what position did you have the ignition key in when doing this test?

What kind of transmission do you have (manual or auto)? If manual, any issues with the clutch start switch? If auto, any issues with the park/neutral position switch?

I suspect the reason you are asking a lot of questions about the COR is that you suspect your fuel pump is not working which is causing you an inability to start the engine?
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Old 11-19-2012, 12:12 PM   #3 (permalink)
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A Cam Position Sensor problem can stop fuel pump if I remember correctly, test don't replace.
Crank position sensor stops spark.

I don't think the 1997 would have an inertia switch.
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Old 11-19-2012, 01:01 PM   #4 (permalink)
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Thanks for chiming in,
I was checking for 12VDC when I put the ign. sw. to the 'ON' pos. I was under the assumption I would get 2 seconds of power. Then the crank positon sensor give the ECU feedback that the motor is turning thereby giving me continuous power to the fuel pump.
Maybe I have to go to 'START' to get the 2 seconds worth? I'll have to check the manual when I get home.

It is an automatic, there is a neutral safety switch that I should check.

This all started about 2 weeks ago, MIL came on with a P0172 code (right bank too rich), cleared it, came back a week later, cleared it again, then the car would start but wouldn't accelerate, in sub-idle mode. Towed home, read codes, same P0172 but with a P1133 (A/F sensor) upstream O2 sensor too rich. So I test the sensor, heating element (OK), voltage steady at .7VDC. Book says it should switch from .1 to .9VDC, so I thought that may be a problem. I replace it, nothing. Several other troubleshooting tips were (to make a long story short) check fuel pressure. I do that with (0) psi. Fine, given the age and mileage I can accept that it is the pump. I go to replace it and just for the heck of it I decided to bench check it. 60 psi and holding. Dang, so I check for power at the pump and 0 VDC. So I troubleshoot the system for power, I can manually supply 12VDC at the COR relay and make the pump work. I've checked the relays, swapped it with the EFI relay, nothing. I basically troubleshooted the system so far as to tell me the the power for the relay holding coil just isn't there.
So far I think I need to see in detail what supplies the ECU information to allow power to the pump.
Thanks again,
Henry
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Old 11-19-2012, 02:26 PM   #5 (permalink)
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If you goggle: scribd 1999 camry wiring

First link should be to an on-line manual
very detailed on what's where and electrical schematics for troubleshooting

I have used this a few times for my 1997 2.2l(5SFE) found it to be accurate

Last edited by RonR; 11-19-2012 at 02:28 PM.
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Old 11-19-2012, 05:37 PM   #6 (permalink)
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What's a COR?
__________________
2000 Camry LE 6-cyl, 77,000 - 230,000, traded it for a
2001 Camry XLE, 6-cyl, 87,000 - 105,000 and counting.
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Old 11-19-2012, 06:06 PM   #7 (permalink)
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Quote:
Originally Posted by ajkalian View Post
What's a COR?
Circuit Opening Relay
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Old 11-19-2012, 06:11 PM   #8 (permalink)
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Quote:
Originally Posted by gejettest View Post
Thanks for chiming in,
I was checking for 12VDC when I put the ign. sw. to the 'ON' pos. I was under the assumption I would get 2 seconds of power. Then the crank positon sensor give the ECU feedback that the motor is turning thereby giving me continuous power to the fuel pump.
Maybe I have to go to 'START' to get the 2 seconds worth? I'll have to check the manual when I get home.

It is an automatic, there is a neutral safety switch that I should check.

This all started about 2 weeks ago, MIL came on with a P0172 code (right bank too rich), cleared it, came back a week later, cleared it again, then the car would start but wouldn't accelerate, in sub-idle mode. Towed home, read codes, same P0172 but with a P1133 (A/F sensor) upstream O2 sensor too rich. So I test the sensor, heating element (OK), voltage steady at .7VDC. Book says it should switch from .1 to .9VDC, so I thought that may be a problem. I replace it, nothing. Several other troubleshooting tips were (to make a long story short) check fuel pressure. I do that with (0) psi. Fine, given the age and mileage I can accept that it is the pump. I go to replace it and just for the heck of it I decided to bench check it. 60 psi and holding. Dang, so I check for power at the pump and 0 VDC. So I troubleshoot the system for power, I can manually supply 12VDC at the COR relay and make the pump work. I've checked the relays, swapped it with the EFI relay, nothing. I basically troubleshooted the system so far as to tell me the the power for the relay holding coil just isn't there.
So far I think I need to see in detail what supplies the ECU information to allow power to the pump.
Thanks again,
Henry
I have a 93 Celica 5S-FE, not a 97 Camry 5S-FE. I would think the operation of the fuel pump between the two would be the same, but I certainly don't know this without a doubt. But, for the 93 Celica 5S-FE, there is not integration relay that primes the fuel pump for a couple seconds when the ignition key is in the "ON" position. If your 97 Camry 5S-FE operates the same, then you would not have any fuel pressure or any voltage going through the COR when the ignition key is turned to "ON". The fuel pump is supposed to operate for the first time when the ignition key is turned to the "START" position.

So if this is how your Camry is supposed to start the fuel pump, you will need to do your testing over again, this time bumping the starter (ignition switch to the "START" position) to see if you get voltage to the COR and to see if the fuel pump operates
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Old 11-19-2012, 06:32 PM   #9 (permalink)
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Page 80 of the scribd manual shows a 5amp IGN fuse as power that relay, for the 5SFE engine.
Doesn't look like the clutch or P/N switch would effect Fuel pump, they are on the starter motor circuit.

The 5A fuse is in the inside fuse panel above the drivers left leg, labelled IGN

Last edited by RonR; 11-19-2012 at 06:37 PM.
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Old 11-19-2012, 06:45 PM   #10 (permalink)
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Quote:
Originally Posted by RonR View Post
Page 80 of the scribd manual shows a 5amp IGN fuse as power that relay, for the 5SFE engine.
Doesn't look like the clutch or P/N switch would effect Fuel pump, they are on the starter motor circuit.

The 5A fuse is in the inside fuse panel above the drivers left leg, labelled IGN
Then my 93 Celica 5S-FE auto is wired differently than this 97 Camry 5S-FE auto.

In my shop manual wiring diagram, the ignition switch ST1 ("START" position) output goes to the Park/Neutral Position Switch, and if that switch is closed (in PARK or NEUTRAL), then circuit continues to the starter relay and to the circuit opening relay (one circuit output from the Park/Neutral Position Switch splits and goes to both the starter relay and the circuit opening relay). And this is how my fuel pump operates - it turns on when the ignition key is in the "START" position, along with the starter, then continues once the ECM determines the engine has initiated a start.

From your response, just remember the COR is what turns the fuel pump on, and in the case of the 93 Celica 5S-FE auto, the COR is in the starter motor circuit.

Last edited by 93celicaconv; 11-19-2012 at 06:47 PM.
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Old 11-19-2012, 07:16 PM   #11 (permalink)
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The wiring diagram I am looking at shows if the key is in the "drive" position or the Start position the COR relay should be powered, via the 5A IGN fuse, by powered I mean the relay is now closed so if the Fuel Pump contact has power then it would be passed to the pump.

The Start position activates the starter relay but via the P/N switch(or clutch switch), so fuel pump relay(COR)would be on in either position.

Last edited by RonR; 11-19-2012 at 07:24 PM.
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Old 11-19-2012, 07:30 PM   #12 (permalink)
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Quote:
Originally Posted by RonR View Post
The wiring diagram I am looking at shows if the key is in the "drive" position or the Start position the COR relay should be powered, via the 5A IGN fuse, by powered I mean the relay is now closed so if the Fuel Pump contact has power then it would be passed to the pump.

The Start position activates the starter relay but via the P/N switch(or clutch switch), so fuel pump relay(COR)would be on in either position.
First, you've just concluded that the COR is in the starer motor circuit, so the starter needs to be energized before the fuel pump turns on the first time.

Second, my my 93 Celica, the Part/Neutral Position Switch comes before the starter relay and before the COR - so the Park/Neutral Position Switch plays a major part if the COR gets power (and hence the fuel pump runs) just like it does if the starter is activated or not. So the Camry power wiring must be different in this regards. But to be perfectly honest, why would Toyota allow the fuel pump to turn on with the ignition key in the START position if the started cannot be activated due to the Park/Neutral Position Switch? That doesn't make sense to me, but it must be the way the Carmy wiring logic is set up.
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Old 11-24-2012, 10:38 AM   #13 (permalink)
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Thanks for all the replies folks,
I tried to see if I had voltage to the G-R wire during 'START', nothing there. So my wife says just put it all together and see what happens. Well, it started and the fuel pump is purring away. It was all good! I don't know what fixed it, very frustrating.
The car is running perfect, but then my daughter got into an accident, crumpled up the hood, grill/bumper and radiator core support. Luckily I have a spare hood and bumper assy. obtained from other minor bumps.
Now the car will crank but not start. I thought there might me an enertia switch or something, no air bags were deployed and the car will not move out of 'PARK' on the auto trans. The CHP pushed the car out of the freeway lanes, I hope the trans isn't ruined.
The accident didn't push anything in the engine compartment into the trans, the only thing that was touched was the exhaust pipe shield. She is very lucky, no one hurt.
Thanks again,
Henry
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Old 11-24-2012, 11:12 AM   #14 (permalink)
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Check this DIY about the neutral safety switch
DIY: Neutral Safety Switch Cleaning

It fits the no start stuck shifter.
Read whole DIY first, you could just need an adjustment.
The sudden stop could have jarred it.

Yes, very good no one was hurt, cars can be fixed.

Last edited by RonR; 11-24-2012 at 01:43 PM.
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Old 11-24-2012, 11:16 AM   #15 (permalink)
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Quote:
Originally Posted by gejettest View Post
Thanks for all the replies folks,
I tried to see if I had voltage to the G-R wire during 'START', nothing there. So my wife says just put it all together and see what happens. Well, it started and the fuel pump is purring away. It was all good! I don't know what fixed it, very frustrating.
The car is running perfect, but then my daughter got into an accident, crumpled up the hood, grill/bumper and radiator core support. Luckily I have a spare hood and bumper assy. obtained from other minor bumps.
Now the car will crank but not start. I thought there might me an enertia switch or something, no air bags were deployed and the car will not move out of 'PARK' on the auto trans. The CHP pushed the car out of the freeway lanes, I hope the trans isn't ruined.
The accident didn't push anything in the engine compartment into the trans, the only thing that was touched was the exhaust pipe shield. She is very lucky, no one hurt.
Thanks again,
Henry
First, sorry to hear about the subsequent accident. That is very unfortunate. I hope your daughter is OK.

Second, when you said you pulled it, what exactly does that mean? Do you mean you pulled the COR out of the socket, and the car started & ran normally without the COR? If so, there is a wiring problem somewhere there.

Now with the accident, I don't know what could all be going on. If your car doesn't come out of park, I would look to see if your shift linkage at the front of the engine (facing the radiator) got bent or broken in any way from the accident.
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