hard reset
#41
03-21-2011, 07:59 PM
Veteran Member
wow I guess Ive been doing a hard reboot wrong all these past 13 years........
For ya'll that dont remember, you have to have a COMPLETE circuit for power to flow. If the negative(or pos) is unhooked from the battery you can touch the DISCONNECTED negative to the STILL CONNECTED(or visa/versa) Positive. There is not a complete circuit and no power flows. you can disconnect both if you feel more comfortable, but its not neccessary, it just takes more time. The reason I and others say disc the negative is 2 reasons
1) it useally the closest and easiest to access
2) theres is useally little or nothing else hooked to it
The reason it works on the capacitors is THEY still have a complete circuit on the car so you are giving their positive terminal a path to ground to discharge them. And since the ignition provides a mechanical link to circuits that are isolated. You can/should also switch the key to the on position while the battery is unhooked and hard reboot again. Then shut off the key and go back and reconnect the battery.....and no a hard reboot will not clear codes on ODBII. While it MIGHT, turn off a check engine light(depending on WHAT, the stored codes are) they DO NOT go away. There are codes that will only show when active/pending, and if you shut off the ignition they may not show even with Jaguars IDS(again it depends on the code/situation)
For ya'll that dont remember, you have to have a COMPLETE circuit for power to flow. If the negative(or pos) is unhooked from the battery you can touch the DISCONNECTED negative to the STILL CONNECTED(or visa/versa) Positive. There is not a complete circuit and no power flows. you can disconnect both if you feel more comfortable, but its not neccessary, it just takes more time. The reason I and others say disc the negative is 2 reasons
1) it useally the closest and easiest to access
2) theres is useally little or nothing else hooked to it
The reason it works on the capacitors is THEY still have a complete circuit on the car so you are giving their positive terminal a path to ground to discharge them. And since the ignition provides a mechanical link to circuits that are isolated. You can/should also switch the key to the on position while the battery is unhooked and hard reboot again. Then shut off the key and go back and reconnect the battery.....and no a hard reboot will not clear codes on ODBII. While it MIGHT, turn off a check engine light(depending on WHAT, the stored codes are) they DO NOT go away. There are codes that will only show when active/pending, and if you shut off the ignition they may not show even with Jaguars IDS(again it depends on the code/situation)
I think there is just a little confusion between what StrateLoss thinks we mean by "disconnect the negative battery cable" and what Brutal understands it to mean. I think StrateLoss thought we meant to disconnect the end of the cable that is connected to the car and touch it to the positive terminal. That would create a short circuit directly between the + and the - terminals on the batt. The cable would melt in just a few seconds. When we say to touch the negative lead to the positive terminal, we mean to disconnect the negative at the post on the battery, leaving the other end connected to the chassis. Then when you touch the negative cable to the positive terminal on the battery, there is nothing at all hooked to the negative terminal. Any electricity stored in the electrical system drains out through the negative cable and into the chassis.
Damn... I just realized that Brutal's post was from last summer.
Oh well... I spent five minutes typing it. I'm posting it. I don't care that it's old news.
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#42
03-21-2011, 09:19 PM
Veteran Member
But, deep down, they would really prefer a youtube video.
#44
05-01-2011, 07:23 AM
IF YOU WANT CODE HELP PLEASE:
Put the letter in front of the number. Jag uses two 1516's. The first one is C1516 and the other is P1516.
My Equus 3130 Scan Tool reads generic and manufacturer codes including Jaguar codes, including transmission. Read the features charts before buying. Also, watch out, some that read ABS codes only do it for a few manufacturers.
Broken wires or bad connections need to be checked for. You do know that rodents love to chew wires.
Put the letter in front of the number. Jag uses two 1516's. The first one is C1516 and the other is P1516.
My Equus 3130 Scan Tool reads generic and manufacturer codes including Jaguar codes, including transmission. Read the features charts before buying. Also, watch out, some that read ABS codes only do it for a few manufacturers.
Broken wires or bad connections need to be checked for. You do know that rodents love to chew wires.
I did get a trans fault a couple of times.
One day car wouldn't go into 1st it seemed.
Will I need a rebuild on the trans?
The other 95% of the time, car drives just fine, except belt screech.
#46
03-23-2013, 08:52 AM
please, dont touch the negative cable to the positive battery terminal.
you want to ground out the power from the circuits to the chasis, not from the battery to the chasis. thats very dangerous !
disconnect the positive and negatives cables, and touch the 2 together. Even simple 1 seconds contact will be fine, but let them touch each other for 10 minutes to drain the power from the capacitors in the cars ecu's.
like I said, DONT touch the negative cable to the positive battery post.
you want to ground out the power from the circuits to the chasis, not from the battery to the chasis. thats very dangerous !
disconnect the positive and negatives cables, and touch the 2 together. Even simple 1 seconds contact will be fine, but let them touch each other for 10 minutes to drain the power from the capacitors in the cars ecu's.
like I said, DONT touch the negative cable to the positive battery post.
Not so. As long as at least ONE of the battery's terminals isn't connected to anything the cables from the car can be touched together. The battery is no longer in the circuit.
NEVER jump the battery's terminals or you'll get a fast welding lesson and perhaps a exploding battery.
Last edited by ross1; 03-23-2013 at 08:55 AM.
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#47
03-23-2013, 09:30 AM
Senior Member
Proper Hard Reset
I know I shouldn't comment on this OLD thread, but here goes.
While a Hard Reset is very easy to do, getting the connections wrong can have catastrophic/dangerous results, so here is how it's done safely.
1. Turn Key OFF
2. Remove Negative Battery Terminal from the Negative Battery Post (10mm Wrench)
3. Turn Key ON
4. Touch Negative Terminal End to Positive Terminal End and hold there for 15 'ish seconds (Positive Terminal will still be connected to Positive Battery Post)
5. Turn Key OFF
6. Reconnect Negative Battery Terminal back to Negative Battery Post
NOTICE: On First Start after the Hard Reset, let the car idle for a minute or two without touching throttle. This allows the computers to recalculate the throttle position, etc... Also, the car may drive differently for an hour or so while it's relearning your driving habits.
See Attached Photo showing Correct Short for Hard Reset
NOTICE: NOTHING CONNECTED TO NEGATIVE TERMINAL
While a Hard Reset is very easy to do, getting the connections wrong can have catastrophic/dangerous results, so here is how it's done safely.
1. Turn Key OFF
2. Remove Negative Battery Terminal from the Negative Battery Post (10mm Wrench)
3. Turn Key ON
4. Touch Negative Terminal End to Positive Terminal End and hold there for 15 'ish seconds (Positive Terminal will still be connected to Positive Battery Post)
5. Turn Key OFF
6. Reconnect Negative Battery Terminal back to Negative Battery Post
NOTICE: On First Start after the Hard Reset, let the car idle for a minute or two without touching throttle. This allows the computers to recalculate the throttle position, etc... Also, the car may drive differently for an hour or so while it's relearning your driving habits.
See Attached Photo showing Correct Short for Hard Reset
NOTICE: NOTHING CONNECTED TO NEGATIVE TERMINAL
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#48
03-23-2013, 10:24 AM
Senior Member
Provided you've disconnected the negative lead from the BATTERY terminal & there is NOTHING touching the battery negative terminal, then it's fine to touch the end of the now disconnected negative lead to the battery positive lead.
There won't be any short-circuits because there is nothing at all connected to the battery negative terminal-all you're doing is connecting the positive lead to the disconnected end of the negative lead, after it's been removed from the battery negative terminal.
Vehicle ECU's & modules usually have smoothing capacitors inside them between the negative & positive rails, so when you disconnect the battery these capacitors may still hold a residual charge.
So, with the battery completely removed from the circuit & NOTHING AT ALL touching the battery negative terminal, connecting the disconnected negative lead end to the positive terminal will short-circuit the supply rails at the ECU's & modules to discharge the internal capacitors.
You are effectively placing a direct short-circuit across the vehicle wiring, which is why the battery has to be COMPLETELY disconnected on at least 1 of it's terminals-if you don't make sure the battery is completely isolated from the vehicle wiring, then you will have a 'nasty experience' by touching the leads together & may well require a fresh set of underwear...
You're not trying to short-circuit the battery, but to short-circuit the main vehicle wiring with the battery COMPLETELY out of circuit...
There won't be any short-circuits because there is nothing at all connected to the battery negative terminal-all you're doing is connecting the positive lead to the disconnected end of the negative lead, after it's been removed from the battery negative terminal.
Vehicle ECU's & modules usually have smoothing capacitors inside them between the negative & positive rails, so when you disconnect the battery these capacitors may still hold a residual charge.
So, with the battery completely removed from the circuit & NOTHING AT ALL touching the battery negative terminal, connecting the disconnected negative lead end to the positive terminal will short-circuit the supply rails at the ECU's & modules to discharge the internal capacitors.
You are effectively placing a direct short-circuit across the vehicle wiring, which is why the battery has to be COMPLETELY disconnected on at least 1 of it's terminals-if you don't make sure the battery is completely isolated from the vehicle wiring, then you will have a 'nasty experience' by touching the leads together & may well require a fresh set of underwear...
You're not trying to short-circuit the battery, but to short-circuit the main vehicle wiring with the battery COMPLETELY out of circuit...
#49
03-23-2013, 04:13 PM
As ALWAYS Brutal is correct. Removing the ground cable from the battery terminal and then touching the positive terminal is safe. Removing the ground cable and the positive cable like you are going to remove the battery and then touching the two cables together works as well, but takes more time. Reset helps with some unexplained quirks that don't set codes, but the OBD II reader is the way to clear codes. Not all readers will clear all codes. I had a transmission rebuilt and still had faults displayed.
Used a different reader to clear them and they have been gone for 14 months.
Used a different reader to clear them and they have been gone for 14 months.
#51
07-10-2015, 02:22 AM
Senior Member
I personally have never had a Radio Code issue on ANY car, but I believe I've been lucky. It would not be a bad idea to have that code available. With that said, I reset my XJR many times without loosing the code. YMMV
#52
07-10-2015, 02:57 AM
Coded radios are the norm in UK and most of Europe. They are very rare but not unknown in the USA.
Graham
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#53
07-14-2015, 07:20 PM
wow I guess Ive been doing a hard reboot wrong all these past 13 years........
For ya'll that dont remember, you have to have a COMPLETE circuit for power to flow. If the negative(or pos) is unhooked from the battery you can touch the DISCONNECTED negative to the STILL CONNECTED(or visa/versa) Positive. There is not a complete circuit and no power flows. you can disconnect both if you feel more comfortable, but its not neccessary, it just takes more time. The reason I and others say disc the negative is 2 reasons
1) it useally the closest and easiest to access
2) theres is useally little or nothing else hooked to it
The reason it works on the capacitors is THEY still have a complete circuit on the car so you are giving their positive terminal a path to ground to discharge them. And since the ignition provides a mechanical link to circuits that are isolated. You can/should also switch the key to the on position while the battery is unhooked and hard reboot again. Then shut off the key and go back and reconnect the battery.....and no a hard reboot will not clear codes on ODBII. While it MIGHT, turn off a check engine light(depending on WHAT, the stored codes are) they DO NOT go away. There are codes that will only show when active/pending, and if you shut off the ignition they may not show even with Jaguars IDS(again it depends on the code/situation)
For ya'll that dont remember, you have to have a COMPLETE circuit for power to flow. If the negative(or pos) is unhooked from the battery you can touch the DISCONNECTED negative to the STILL CONNECTED(or visa/versa) Positive. There is not a complete circuit and no power flows. you can disconnect both if you feel more comfortable, but its not neccessary, it just takes more time. The reason I and others say disc the negative is 2 reasons
1) it useally the closest and easiest to access
2) theres is useally little or nothing else hooked to it
The reason it works on the capacitors is THEY still have a complete circuit on the car so you are giving their positive terminal a path to ground to discharge them. And since the ignition provides a mechanical link to circuits that are isolated. You can/should also switch the key to the on position while the battery is unhooked and hard reboot again. Then shut off the key and go back and reconnect the battery.....and no a hard reboot will not clear codes on ODBII. While it MIGHT, turn off a check engine light(depending on WHAT, the stored codes are) they DO NOT go away. There are codes that will only show when active/pending, and if you shut off the ignition they may not show even with Jaguars IDS(again it depends on the code/situation)
As always Brutal is correct. You have to have a COMPLETE circuit for current to flow. I only have 4 years experience doing it wrong.
#54
07-15-2015, 09:56 AM
Just a bit more to add regarding which cable to disconnect. The ground cable should always be the first cable disconnected and the last re-connected just to avoid arcing should the wrench touch metal.
I know this is elementary but I've seen a battery blow the top off and splatter acid in a friend's face when a spark ignited the battery gases. He survived it just fine, your experience may differ.
I know this is elementary but I've seen a battery blow the top off and splatter acid in a friend's face when a spark ignited the battery gases. He survived it just fine, your experience may differ.
#55
07-15-2015, 10:10 AM
Senior Member
Just a bit more to add regarding which cable to disconnect. The ground cable should always be the first cable disconnected and the last re-connected just to avoid arcing should the wrench touch metal.
I know this is elementary but I've seen a battery blow the top off and splatter acid in a friend's face when a spark ignited the battery gases. He survived it just fine, your experience may differ.
I know this is elementary but I've seen a battery blow the top off and splatter acid in a friend's face when a spark ignited the battery gases. He survived it just fine, your experience may differ.
True, it's elementary, but we all make silly mistakes occasionally. My father dropped a wrench and it hit the terminals and held on till the battery blew.
#56
07-21-2015, 10:10 AM
I just got a new battery the other day and did a "hard reset" without the battery in the car. Touching the positive and negative cables together without being connected to the battery at all. Does this work the same, or does the positive actually need to be connected to the battery still?
#58
09-06-2015, 05:51 PM
My 2005 xj8L has been throwing codes p0171 and p0174, citing lean mixture on both banks, and sometimes showing restricted driving. I cleaned and then replaced the MAF. No change. Mine is a low mileage car, and drives beautifully but any sudden change in control would set off the codes. I was about to waste of lot of money chasing down the oxygen sensors....following other forum 'experts',
Then I did a ECU reset, putting both battery cables together. Now it feels perfect...no more codes (so far), and it starts easier (without a needed warm-up electrical delay). Big problem solved in 15 minutes and no cost.
Thanks for the advice.
Then I did a ECU reset, putting both battery cables together. Now it feels perfect...no more codes (so far), and it starts easier (without a needed warm-up electrical delay). Big problem solved in 15 minutes and no cost.
Thanks for the advice.
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#59
06-15-2021, 12:01 PM
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#60
06-15-2021, 01:05 PM
Welcome to the forums Bluffer,
Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some information about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.
Graham
Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some information about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.
Graham
