95 gmc obd1 code 13

[loom383]

Hello, I have a 95 gmc ext cab k1500 with a 5.7l 350. My check engine light will come on after driving(usually around 10-20 mins) and sometimes will shut back off. The code is reading as 13 Oxygen sensor circuit open or no activity. Where is the o2 sensor(s) located? and does this usually mean my 02 sensor is bad? or the wire is broken/shorted? Any help would be appreciated.

 

[sewlow]

CODE 13
Trouble Code 13 indicates that the exhaust stream oxygen-content sensor (O2 sensor) is not responding as expected. When cold, the sensor is 'biased' by the ECM to about 450 millivolts. Before it warms to at least 600 deg F (315 deg C) it acts as an open circuit and when the ECM reads it, it reads the 450 mV bias. The ECM expects the sensor to warm in a short period of time and begin sending its own voltages. The general conditions for this code getting set are:
? engine running at least 2 minutes
? coolant temperature at least 50 deg C (122 deg F)
? O2 voltage not fluctuating (i.e steady between 350 and 550 mV)
? TPS signal above idle
? all above conditions met for 60 seconds

Typical causes may include:
1. Defective or degraded O2 sensor
2. Deposit-contaminated O2 sensor (running leaded fuel, RTV silicone deposits etc)
3. Corroded/defective O2 sensor connection
4. Defective sensor ground circuit
5. Defective connection at ECM
6. Defective ECM
NOTE: If codes 21 and/or 22 are also present cause '4' above should be checked first.

 

[loom383]

After looking closely It seems like my truck does not have any o2 sensors. It appears that each manifold has plugs in it, and right before the cat there is a plug in the exhaust where the 02 sensor would go. It seems like there is no emission system on my truck. Is it possible to even pass without there even being a system? any help would be great I am lost for what I should do next.

 

[low4x4]

on a 95 there is only one...located on the drivers side just below the manifold above the y connection...1 purple wire goes to it

 

[loom383]

weird, I have a blue wire that is clipped and capped off. Ill check to see if I can find a purple wire. Thanks!

 

[1997chevydriver]

On a 95 it should have a heated O2 sensor. On my 94 it is just before the cat after the y pipe. IIRC the 1 wire o2 sensors ended in 93

Sent from somewhere in MN

 

[loom383]

how many wires should be going to my 02 sensor then? and any clue what colors? Thanks for any help!

 

[1997chevydriver]

3..... purple, pink (or pink/white) and black

Sent from somewhere in MN

 

[loom383]

3..... purple, pink (or pink/white) and black

ok thanks!

 

[axisT6]

I am curious now. Your truck should have the O2 just upstream of the cat. The O2 is very critical in an EFI system. Let us know what you find.