Code 26 (1 Viewer)

[Brentbba]

Moj - first of the tests running at 2500 rpm - I get more than 8 voltage spikes connecting to VF1 or VF2, can't remember right now and nothing on the other one. Test steps seem to indicate to me that voltage on one OR the other is all you are looking for. That would indicate to me that the everything is normal. I counted 15 spikes in the voltage in the 10 seconds. I think I was too timid to shove the probes down into the terminals to try to do the other voltage tests.

I give up - taking the truck in.

 

[MoJ]

If you want to check the ground before taking it to the mechanic:

Ground: The engine ground bolt is right next to the oil filter at about the 5 o'clock position. Notice it connects to the wiring harness going to the battery neg. which in turn grounds to the body. Check each bolt as well as the battery terminals. You can also use the ohm setting on your meter to check that there's a connection between any two points along that route. (It should peg out.)


You can also start down the list posted by 80tlylc in #6. Also might not hurt to look at the wiring harness for the common damaged insulation problem where it passes by the egr.

 

[Brentbba]

Did you get voltage in both VF1 and VF2? I'm only getting voltage on one side. Barring the ECM, it looks like one of the two sensors is bad...AGAIN. Standing damn order with Dan for O2 sensors. I'm 'assuming' the 1 and 2 on the VF refer to the #1 and #2 O2 sensors.

 

[MoJ]

Are you referring to the step that has you check voltage between VF1 (or VF2) and E1 w/o the paper clip connected?

 

[Brentbba]

Step 3 above with the paper clip betwen E1 and TE1 with the voltmeter between E1 and VF1 (or VF2). I get plenty of meter spikes with the meter connected to 1 or 2 (can't remember which one now) and none on the other one. Wondering if I should see volt spikes on both VF1 and VF2 when tested. Since the FSM says 'or' I'm thinking one or the other, not each tested separately. Further testing where you disconnect E1 and TE1 and test the voltage between E1 an VF1 (VF2) separately? would then determine which O2 sensor may be malfunctioning if there are zero volts measured. Hope that makes more sense.

 

[MoJ]

Step 3 above with the paper clip betwen E1 and TE1 with the voltmeter between E1 and VF1 (or VF2). I get plenty of meter spikes with the meter connected to 1 or 2 (can't remember which one now) and none on the other one. Wondering if I should see volt spikes on both VF1 and VF2 when tested. Since the FSM says 'or' I'm thinking one or the other, not each tested separately. Further testing where you disconnect E1 and TE1 and test the voltage between E1 an VF1 (VF2) separately? would then determine which O2 sensor may be malfunctioning if there are zero volts measured. Hope that makes more sense.

The voltage spikes should be on both. I read the "or" as meaning VF1 or VF2 depending on which o2 sensor you're testing. If you're not seeing the voltage spikes on one of them then you should follow the flow chart for "less than 8 times". At that point you remove the paper clip, keep the rpm's at 2500 and then seperately measure voltage between VF1 and E1 and then VF2 and E1. (you'll have to check both since you don't remember which one had 0 spikes) If you get more than 0 volts, it tells you to replace the 02 sensor. If you get 0, then it leads you to the additional tests.

Also, it you're have trouble getting the probe in the hole you can stick a piece of wire/paperclip in there to create an extension for the probe to contact.

 

[Brentbba]

Gotcha! At least spikes on one side tell me the ECM is ok. I'll certainly redo using those steps...and yes, already was going to electrical tape a paper clip to the probe to make it easier to get good contact in VF1 and VF2.