CA smog issue "Minimum voltage not detected"

[Evan_in_CA]

My son's 98 XJ is having this issue. No codes, runs great, zero obvious problems. We're going to get it smogged and two different shops get this error when they try to smog. Both places' computers say that it is ready to smog, but this happens when they actually try to start the tests.

Error on the last machine is "Minimum voltage not detected! Turn key fully off, re-seat connector, then re-start engine." Tech said the problem is "something electrical, that shit is expensive" so not a lot of help.

I'm assuming that one of the pins on the OBD port should have a signal but does not, but not sure how to go about figuring out which one. We checked pin 1 to pin 8 for voltage and get 14.1 so that seems fine. Advice?

 

[Evan_in_CA]

For clarity, 1998 XJ, 4.0, auto, 4x4

 

[RCP Phx]

Some of this may be hard to comprehend. When dealing with corrosion you can have voltage with no current flow. Specially since today's digital meters have such a high impedance leads, the older Simpson meters actually drew some current in their function.

 

[Evan_in_CA]

OK, it's a california vehicle so there's virtually no corrosion issues anywhere. I wish I could find a pinout diagram so we could at least test each pin to see if we can narrow down which one is the issue so we can at least figure out what system we need to be looking at.

 

[RCP Phx]

That's all available in a FSM!

 

[lawsoncl]

Does an OBD reader power up and work?

 

[Saudade]

Pin 16 should always have battery voltage through fuse 17 in the PDC. Pins 4&5 are grounds.

 

[Evan_in_CA]

That's all available in a FSM!

Sorry, what's an FSM?

 

[Evan_in_CA]

Pin 16 should always have battery voltage through fuse 17 in the PDC. Pins 4&5 are grounds.

Will check this, thank you

 

[Evan_in_CA]

Does an OBD reader power up and work?

Yes, OBD scanner powers up and works fine, zero codes logged.

 

[RCP Phx]

Sorry, what's an FSM?

Factory Service Manual

 

[lawsoncl]

Pin 16 should always have battery voltage through fuse 17 in the PDC. Pins 4&5 are grounds.

He said he had voltage on those pins, so perhaps a bad ground versus no power.

 

[Saudade]

Perhaps. He said he did pins 1-8. He was unclear is he meant 12v on all of them or just one.

Here's the pinout.

CAV CIRCUIT FUNCTION
1 - -
2 - -
3 D1 18VT/BR CCD BUS (+)
4 Z1 18BK GROUND
5 Z12 18BK/TN GROUND
6 D20 20LG/BK SCI RECEIVE
7 D21 20PK SCI TRANSMIT/ ISO 9141K
8 - -
9 - -
10 - -
11 D2 18WT/BK CCD BUS (-)
12 - -
13 - -
14 - -
15 - -
16 F34 18TN/BK FUSED B(+)

The ones with dashes are not used.

 

[Johnnie Walker]

I know that on some Mopar stuff the battery temp sensor can affect charging and electrical.

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