Dreaded trans. Failsafe prog.

[Oldmactech]

FWIW this is the 09/03 model so apparently there were some changes made in that production month as referenced by the Bentley manual.

This picture shows a few crimped wires at the AGS but these are the only crimps I have been able to find.
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[Oldmactech]

This connector pulled from the AGS has 2 red/white stripe wires and displays continuity to the red/ws connectors on both banks of upstream O2 pin connectors. Also on the black wire pins.

No continuity to anything on the downstream side.


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[andrewwynn]

Trace those two wires they should mate up with the four O₂ heaters


If those are the red/white hot to the EGS. They look brown/white maybe in photo

[Oldmactech]

Two in the foreground are red/white stripe.
Only a few inches from this connector the wires disappear into a larger wire bundle wrapped in black tape that all goes into a plastic conduit. I guess I have to either disassemble the black tape and locate the splice or peal off the sheath of the suspect O2 wires and look for a shorted wire.

FYI it get continuity on both upstream wires (zero on downstream) at this connector as well as continuity to chassis ground in 4 of the six connecting points.


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[andrewwynn]

Take off the tape e hand had to remove that before I found that splice. I am pretty certain it was in the e-box right before going into the plastic conduit behind the engine against the firewall.

[Oldmactech]

I took the crimp out where the two larger dia red/ws crimp to the 4 smaller dia red/ws heater wires and got continuity all 4 corners so sorta ruling out a shorted wire except maybe the crimp was bad. Doubt it. Probably put a little solder on the 6 wires before re-crimping to make a surer connection.

Also, pulled the AGS brain to check for broken or bent pins. Looks like it is held together by tabs on 4 sides. Dare I Jimmy it apart or leave well enough alone?
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[andrewwynn]

Explain "got continuity". When disconnected you aren't supposed to get any Reading. When unplugging the O₂ sensors the wires should all read open.


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[Oldmactech]

Took the red/ws crimp apart, tested continuity on each line and all good. Re crimped, blew the fuse….

Not surprised.

Will test the other wires coming off the same bus but out of time today.

Sheesh.


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[Clavurion]

Separate the red/white wires from the common point and measure each one separately for resistance against ground. If the end loads (lambda sensors and EGS connector) are removed the resistance against ground should be infinite. If the end loads are connected the resistance should be above ~2 ohm. If the resistance on some wire is lower indicating a short to ground separate that wire and connect all the other wires back together and install a new fuse.

[Oldmactech]

I think I’m close. Did Resistance test you and Andrew Wynn suggested. Cut the crimp, separated the red/wS wires and read resistance all OL except one. Of course my DIMM battery died in the process and it got dark so back at it tomorrow. Likely an up stream wire crossed the exhaust manifold but haven’t isolated it yet.

Re-reading your suggestion with the O2’s connected should not read OL? But with O2 pigtails disconnected OL is correct?


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