Even though the indicator lights up in your Power/Comfort switch, that does not mean the switch is working and putting the Transmission Control Unit into Power mode.
The switches had a high failure rate.
Remove and unplug the switch. In the harness are 3 wires. One has a stripe, one is tan, and the other wire is black.
Make a 4″ jumper wire with a male spade at each end.
Plug one end of the jumper wire in the cavity for the tan wire and the other in the cavity for the striped wire of the harness and you’ll be in permanent Power mode.
Stuff the harness back in and reinstall the switch for looks if you want.
Make sure the 7.5 amp “Trans” fuse in the fusebox is good.
If you happen to have a 91 or 92 XJ/MJ and it has the Power/Comfort switch, just jumper the Tan and Blue wires in the harness plug.
NEVER include the black wire when jumpering!!!
Hi cruiser54,
What’s the advantage of bypassing the switch for permanent Power mode? is the MPG affected?
Thanks a lot for your great website!
Your MPG will improve, as will your driveability.
As for the website, you’re welcome!! Keep the questions coming and most of all, enjoy your Renix Jeep!!!
Is there a difference from just leaving the switch set to POWER mode?
I guess one benefit is that I can use that switch for something else 😉
Hi C54,
If MPG and driveability improves in Power mode, then what was the Comfort mode’s advantage?
Also, what do you mean by “driveability”?
Thanks!
It was not an advantage. I have no idea why they did that other than it was something they COULD do with what Aisen-Warner provided them. Comfort mode is obnoxious to me and was to many of my customers at the dealership.
So, Comfort mode did nothing other than lower the MPG and driveability? No other differences?
Also, what do you mean by “driveability”?
Thanks!
I don’t think the Comfort mode reduced MPG. As far as driveability, the Comfort mode was annoying in it’s habits. shifted up too soon, then would downshift too late. I call it Grandma mode.
If Comfort mode didn’t reduce MPG, then what did you mean in your Sept 19, 2016 Reply (that you posted above, on this page), where you replied that an advantage of bypassing the switch for permanent Power mode is that your MPG will improve?
It will improve but not much at all.
You certainly don’t save fuel with it in the Comfort mode, which is a common misconception.
If driving in Power mode reduced fuel consumption, the factory wouldn’t have eliminated the Comfort mode in 91 and later production.
Ha – weird. Looking at my 88 XJ’s original manual right now – where it talks about the Power/Comfort switch, it says about Comfort mode: “…..will upshift at lower speeds for more economical operation.”
So, are you saying that even though Jeep had designed the Comfort mode for more “economical operation” and published that claim in their manual, in reality, the Comfort mode actually did the opposite of what they claimed, and ended up making it operate slightly LESS economically?
It’s as if they never compared the two modes after they built it?
From the owner’s manual:
“Automatic transmission mode selection allows you to select different transmission shift characteristics to suit your driving style and road conditions.
Power: In this mode the transmission will be more responsive. It will upshift at higher speeds under hard acceleration and downshift more quickly.
Comfort: This mode is for normal driving. The transmission will upshift at lower speeds for more economical operation.”
You just quoted the same exact quote I did – I guess we have the same owner’s manual 🙂
According to the same quote we both just posted, Jeep had designed the Comfort mode for more “economical operation” and published that claim in their manual (as we both just posted).
On the other hand, you posted here on this forum on Feb 22 about Comfort Mode: “You certainly don’t save fuel with it in the Comfort mode, which is a common misconception.”
So, Jeep says Comfort Mode is more economical, and you’re saying that in reality, the Comfort mode actually did the opposite of what Jeep claimed, and ended up making it operate slightly LESS economically?
Wouldn’t they have ran tests on which mode was more economical (better mpg)? Did they just outright lie to the public in the manual?
Who knows? The difference in economy was minimal at best. It’s more like a feature that was available for them from the transmission manufacturer and they promoted it. The point I’m trying to make is the Comfort mode is useless. Don’t let that claim in the owner’s manual keep you from bypassing the switch.
Rather than jumper wire why not just put the switch towards power mode and leave it there?
Because many times those junky switches have failed in different ways.
Sometimes they will even light up but not send a signal to the transmission control module. Or be totally defunct.
Aha! My previous question answered. I missed this on the first read. I suspect my switch is defective, because that is the exact behavior I am seeing…no difference when switched.
I have an ’89 comanche pioneer 4×4. 4.0 il6
I bought it from a guy about 4 mo ths ago and i have been chasing the same issue he was which is why he sold it lol.
While driving or idiling (intermittently) its like the engine just loses power and boggs down to almost a stall and backfires into the air box. If ur driving when it happens u just floor the pedal to the floor and boom it speeds right up like it should.
I have replaced the following:
Fuel pump & filter
O2 sensor
MAP sensor
EGR valve & transducer
Pluggs & plugg wires
Cap & rotor
Thermostat
Electrc fan switch
Brake booster grommet
And a few vaccum lines.
Prior to me buying it he had replaced:
Crank sensor
Tps
I removed the exhaust from just in front of the CAT thinking maybe the the cat was clogged up causing excessive back pressure. Nope only thing that did was put some bass n the sound of the truck lol
Any help would be awesome. Also whats the switch on the left of the steering wheel thats identical to the power/comfort switch but has 3 lines on it??
Have you tested fuel pressure. If a new fuel pump was installed and it wasn’t a Bosch, expect an early failure. as a preemptive measure perform my Tip concerning improving the fuel pump ground.
I think the throttle body might be all caddywhompus. The butterfly adj.screw was not touching the plate. The plate wouldnt go in anymore towards the screw so i turned the screw clockwise until it was touching the plate and then about 3 quarter turns past that. I gotta go buy some torx sockets to remove the air i take off the throttle body so i can see the butterfly. Not sure if i did something i shouldnt have haha. Didnt seem to negatively affect actually seemed to not bogg down as much as it was so i figure i must be on the right track
I would make sure the TPS was installed correctly. Maybe try another one. They have been known to be defective out of the box.
Yes it holds the pressure exactly where it is supposed to. No leak down at all
Ever seen this?
http://cruiser54.com/?p=94
Ya thats what made me go outside and look at it as soon as i read it lol. I just gotta get the air intake off the throttle body so i can view the butterfly and set it to the correct spec. The linkage that connects to the plate is super sloppy on my truck. It wiggles side to side super easily. The plate itself doesnt wiggle just the linkage. Is that normal?
Pretty normal for floppy linkage.
I put my hood back on and forgot to attach the hood release any ideas
Try this link:
https://comancheclub.com/forums/topic/829-what-to-do-if-your-hood-release-cable-breaks/
Just to clarify,it says to never use the black wire when bypassing the power-comfort switch,so what do you do with it,disconnect it or just leave it connected?
Just leave it there. I emphasized never using it jumpered since it is a ground.
First…amazing site cuiser54. Resources like this are what make the internet such a great tool.
How do I KNOW the transmission is in “power” mode either by the switch or by bypassing it as shown above?
If you bypass it, it will be in Power mode.
As for the switch, it lights up in Power mode, but there’s no guarantee it’s powering that function of the TCU without checking it out with a pinout and meter.
The other way to tell is… you can feel the difference.
Absolutely. There is a difference.
so there is no need for the ground wire because you are eliminating the switch? just making power mode a constant circuit?
correct. The ground wire is just for the light in the switch.
Glad I did this, I think my switch was intermittently switching itself into comfort mode when I had the switch flipped to power. It would kinda feel like the transmission was slipping when coasting to a slow stop or just to not have to hit the brakes. Then it would feel wimpy and shift at awkward points, it would also shift at strange points going up hills and also shift when it didn’t feel like it should need to. Constant power mode is much better!
Aaron, you have become a poster child for this Tip!!!
That’s exactly what happens.
Haha that’s hilarious! Good to know it wasn’t all just psychological!
It wasn’t. Those switches were real crummy. Intermittent. And when they failed, it was Grandma Shift Mode…….
I hate Grandma mode…
Whether you get better or worse gas mileage in the Comfort mode depends on your driving. “Grandma” mode is a good analogy — if you drive like Grandma (slow take offs, low speeds) gas mileage will stay the same or improve in comfort mode. If you’re an aggressive driver it will go down slightly due to putting a bit more strain on the engine (due to shifting sooner). For normal driving you probably won’t notice much difference in mileage, just a bit slower accelerating due to the sooner shifts. The feature is still there on the later model TCU, it’s just wired to “Power” from the factory and the switch eliminated. You could add a couple wires to the TCU connector and still have it if you wanted, but few would find it useful.
I have a 91 Cherokee. It has no power/comfort switch, but it is shown in the manual. Since it doesn’t have one, would the default be power? If not is there a possibility of changing it?
Absolutely correct!!!
That sensor is not compatible with the Renix system.
is there a pic of the jumper installed for this fix? [sorry, i just don’t want to screw anything up! haha!]
BTW – LOVE this site! it’s a HUGE HELP with me and the 88Comanche #thx
There’s a photo right at the beginning.