Error Code 00310(Cat Temp Sensor) 96 Passat

JohnJTDI

Veteran Member
Joined
Nov 19, 2011
Location
central Wisconson
TDI
1996 Passat 2005.5 jetta
Have looked at a number of older threads re: the fix for this code.My CEL comes on(have cleared couple times) and VAGCOM gives me this code. Fixes range from cutting the wires to the cat sensors and tieing their ends together(didn't work for me or should the ends not be connected as this is nothing more then a short?), installing 10 ohm or 220 ohm or 330 ohm resistor of various wattage. Looking for an update as to what works. With the 310 code does that mean I only have to deal with 1 of the temp sen(G20-and which 1 is G20? front or rear) and not worry about the other sensor(G132) as this would be a different code(312)?? 5th injector has been disabled by plugging fuel line. I also assume it got the company mod for the 5th inj under a previous owner as the car doesn't smoke and the ECU is not black..?? Is it possible to clear error codes using blink codes on this vehicle or is this only possible w/ a scan tool??
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
idi: 1988 Bolens DGT1700H
From the bottom up:
The black case ECU is the BK series. It has limited support for blink code,...limited in that there are about 20~30 different codes covered by the blink de-coding, nowhere near the full listing.
If you have a silver case it is a fully OBD II compatible GQ series, and does not operate the 5th injector, even had a prior owner not defeated it. No blink code support is available with that ECU.

The cat temp sensors still need to be kept within a small temperature (resistance reading) value of each other to avoid fault codes. The only means of accomplishing this is to have both reading a valid temperature (two working sensors), or to have both reading the same false temperature. A 220 ohm resistance is interpreted as being about 70F (20C). Disconnecting the working sensor and substituting a 220 (or so) ohm resistor for each of the sensors will keep the CEL away.

The 10 ohm (but about 1/2 watt capacity) resistor is a spoof for the 5th injector, but since you have a GQ the unit isn't activated anyway. The GQ ECU still checks for it to be present (10 ohm resistance), but it is not ever turned on to operate.
 

JohnJTDI

Veteran Member
Joined
Nov 19, 2011
Location
central Wisconson
TDI
1996 Passat 2005.5 jetta
Cat

From the bottom up:
The black case ECU is the BK series. It has limited support for blink code,...limited in that there are about 20~30 different codes covered by the blink de-coding, nowhere near the full listing.
If you have a silver case it is a fully OBD II compatible GQ series, and does not operate the 5th injector, even had a prior owner not defeated it. No blink code support is available with that ECU.

The cat temp sensors still need to be kept within a small temperature (resistance reading) value of each other to avoid fault codes. The only means of accomplishing this is to have both reading a valid temperature (two working sensors), or to have both reading the same false temperature. A 220 ohm resistance is interpreted as being about 70F (20C). Disconnecting the working sensor and substituting a 220 (or so) ohm resistor for each of the sensors will keep the CEL away.

The 10 ohm (but about 1/2 watt capacity) resistor is a spoof for the 5th injector, but since you have a GQ the unit isn't activated anyway. The GQ ECU still checks for it to be present (10 ohm resistance), but it is not ever turned on to operate.
Thanks for responding! I do have a GQ ECU. Do I need to install a 10 ohm resistor somewhere to get rid of the CEL-not real clear on this. Also for the cat-simply tieing the two wires of each sensor together or possibly tieing all four together should result in same resistance reading(?) or will this not work as it results in an "unrealistic" value??
 

TonyJetta

Top Post Dawg
Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
Is the 5th injector still installed? It's T'd off the fuel supply line to the injection pump.

Tony
 

paramedick

TDIClub Enthusiast, Vendor
Joined
Jul 29, 2001
Location
Versailles, Kentucky
TDI
2015 Audi Q5 TDI, 2000 New Beetle
Thanks for responding! I do have a GQ ECU. Do I need to install a 10 ohm resistor somewhere to get rid of the CEL-not real clear on this. Also for the cat-simply tieing the two wires of each sensor together or possibly tieing all four together should result in same resistance reading(?) or will this not work as it results in an "unrealistic" value??
You need the resistor in the 5th injector wiring. GQ disables it, but still checks continuity of wiring.

No, you will never cure the CAT temp sensor problem without 1)having sensors in place or 2) installing resistors.
 

JohnJTDI

Veteran Member
Joined
Nov 19, 2011
Location
central Wisconson
TDI
1996 Passat 2005.5 jetta
Is the 5th injector still installed? It's T'd off the fuel supply line to the injection pump.

Tony
Yes 5th injector still installed on exhaust but fuel supply lines(T) have been removed/plugged. I believe rest of system(solenoid w/associated wiring) is still intact but not operating. Would hooking both cat sensor wires to one operating temp sensor fool the ECU into thinking no temp difference and not result in an error code/CEL??
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
idi: 1988 Bolens DGT1700H
I don't know if the doubling of the wires to one resistor would result in the same value being received on each pair back at the ECU. I've never tried.
Let me rephrase that.
I don't know if the result will be within an acceptable range. If the value received is cut in half (split between two paths) it may produce two fault codes even though the value is identical.
Faults of these sensors could be resistance too low (shorted to ground), or resistance too high (open or shorted to plus), so there is a limited range of acceptable values in addition to some limit of difference between the two. Matching the values isn't enough, they must both also remain within some minimum and maximum resistance.
A pack of suitable value resistors is under $5 and will provide enough to do multiple cars. The amount of labor to try one sensor to two sets of leads will be about the same as the labor to do two resistors.
 
Last edited:

JohnJTDI

Veteran Member
Joined
Nov 19, 2011
Location
central Wisconson
TDI
1996 Passat 2005.5 jetta
To the lab

I don't know if the doubling of the wires to one resistor would result in the same value being received on each pair back at the ECU. I've never tried.
Let me rephrase that.
I don't know if the result will be within an acceptable range. If the value received is cut in half (split between two paths) it may produce two fault codes even though the value is identical.
Faults of these sensors could be resistance too low (shorted to ground), or resistance too high (open or shorted to plus), so there is a limited range of acceptable values in addition to some limit of difference between the two. Matching the values isn't enough, they must both also remain within some minimum and maximum resistance.
A pack of suitable value resistors is under $5 and will provide enough to do multiple cars. The amount of labor to try one sensor to two sets of leads will be about the same as the labor to do two resistors.
Thanks Lug!! The experiment begins.;)
 

JohnJTDI

Veteran Member
Joined
Nov 19, 2011
Location
central Wisconson
TDI
1996 Passat 2005.5 jetta
Experiment ends

:)I simply connected the two wires from the "bad" sensor to the two wires on the "good" sensor; cleared the error code and haven't seen it since. NO MORE CEL!! (I hope). "Good" sensor is now the only one connected to ECU.
 

torahtom

Well-known member
Joined
Jun 24, 2007
Location
Elizabeth, CO
TDI
1996 Passat Sedan, 230,000
Which Wires to put the resistor in?

From the bottom up:
The black case ECU is the BK series. It has limited support for blink code,...limited in that there are about 20~30 different codes covered by the blink de-coding, nowhere near the full listing.
If you have a silver case it is a fully OBD II compatible GQ series, and does not operate the 5th injector, even had a prior owner not defeated it. No blink code support is available with that ECU.

The cat temp sensors still need to be kept within a small temperature (resistance reading) value of each other to avoid fault codes. The only means of accomplishing this is to have both reading a valid temperature (two working sensors), or to have both reading the same false temperature. A 220 ohm resistance is interpreted as being about 70F (20C). Disconnecting the working sensor and substituting a 220 (or so) ohm resistor for each of the sensors will keep the CEL away.

The 10 ohm (but about 1/2 watt capacity) resistor is a spoof for the 5th injector, but since you have a GQ the unit isn't activated anyway. The GQ ECU still checks for it to be present (10 ohm resistance), but it is not ever turned on to operate.
Lug Nut,

Which of the 4 wires to the cat sensor do I need to solder the resistor in? I cut the wires all the way up to the wiring harness under the air filter box when I replaced the cat. converter with a straight down pipe from ID parts.


 
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