RangeRovers.net Forum banner

1 - 20 of 52 Posts

·
Registered
Joined
·
35 Posts
Discussion Starter #1
97 p38, after a head gasket repair I had instrument cluster issues. Mechanic replaced engine harness and now replaced the becm.
Instrument issues resolved but now it wont start.
Its asking for a security code. Where do I find this? Unfortunately I have a key but no functional key fob.
 

·
Registered
Joined
·
224 Posts
97 p38, after a head gasket repair I had instrument cluster issues. Mechanic replaced engine harness and now replaced the becm.
Instrument issues resolved but now it wont start.
Its asking for a security code. Where do I find this? Unfortunately I have a key but no functional key fob.
 

·
Registered
Joined
·
1,292 Posts
It is known as sychronising (or syncing) the BECM and the engine ECU.
There is a code number that needs to be the same in each to allow it to start. Diagnostics are needed to set it.
Procedure is a bit different whether diesel or Gems/Bosch petrol.
 

·
Registered
Joined
·
35 Posts
Discussion Starter #5
It is known as sychronising (or syncing) the BECM and the engine ECU.
There is a code number that needs to be the same in each to allow it to start. Diagnostics are needed to set it.
Procedure is a bit different whether diesel or Gems/Bosch petrol.
 

·
Registered
Joined
·
1,292 Posts
You need to find someone with suitable diagnostics in order to sychronise the code. I have got a Blackbox systems Faultmate and I copied the following section from the help file:

Security learn mode: When the ignition is turned on, the BECM, providing it is in receipt of a valid mobilization code and is therefore not in an alarmed or immobilised state, sends a coded signal to the GEMS which the Gems then compares against a mobilization code it has stored in it. If the two codes compare OK, the Gems will allow the engine to start. This forms the basis of the immobiliser. If the GEMS ECU, the BECM, or the lockset & key fob is replaced or other data in the BECM is changed, it may be required for the GEMS to re-learn a new mobilization code. This is done by using this function to put the GEMS into Security learn mode whereby the next coded signal it receives is not compared but is instead stored as the master copy. When security learn mode has been entered the ignition must be turned off and turned back on to trigger the BECM into sending the code. The GEMS will check the incoming code and should accept it; however, if there is an error no matter how slight in the codes makeup, the GEMS can reject it, in which case there will be no valid code stored. This situation can be checked by looking at the security learn status in Inputs - Engine and Other which denotes whether the system has a valid code stored or not.

I have got the diesel so haven't actually done a GEMS, but they are similar. You just enter the code in the BECM and save it.

The other way as others have mentioned is to replace both the BECM and engine ECU as a pair from the same donor car. That way they are already synced.
 

·
Registered
Joined
·
35 Posts
Discussion Starter #11
You need to find someone with suitable diagnostics in order to sychronise the code. I have got a Blackbox systems Faultmate and I copied the following section from the help file:

Security learn mode: When the ignition is turned on, the BECM, providing it is in receipt of a valid mobilization code and is therefore not in an alarmed or immobilised state, sends a coded signal to the GEMS which the Gems then compares against a mobilization code it has stored in it. If the two codes compare OK, the Gems will allow the engine to start. This forms the basis of the immobiliser. If the GEMS ECU, the BECM, or the lockset & key fob is replaced or other data in the BECM is changed, it may be required for the GEMS to re-learn a new mobilization code. This is done by using this function to put the GEMS into Security learn mode whereby the next coded signal it receives is not compared but is instead stored as the master copy. When security learn mode has been entered the ignition must be turned off and turned back on to trigger the BECM into sending the code. The GEMS will check the incoming code and should accept it; however, if there is an error no matter how slight in the codes makeup, the GEMS can reject it, in which case there will be no valid code stored. This situation can be checked by looking at the security learn status in Inputs - Engine and Other which denotes whether the system has a valid code stored or not.



I have got the diesel so haven't actually done a GEMS, but they are similar. You just enter the code in the BECM and save it.

The other way as others have mentioned is to replace both the BECM and engine ECU as a pair from the same donor car. That way they are already synced.
Thank you very much.
Let me ask, which Faultmate are you using, the MSV-2 or the FCR. I'm looking at ordering one and not sure which I require.

Thank you.
 

·
Registered
Joined
·
1,292 Posts
I have got the Faultmate MSV-2:


It has been out for quite a while, but on the p38 it still does more than any other system on the market.
The basic hardware is a reasonable price, but it is the cost of the software modules that adds up. You could start on a basic system that is locked to one VIN then add further modules if necessary in the future. It also needs to be connected to a PC with a serial port to get the best out of it.

Guys on here also speak highly of the Nanocom. You need to look at that as well:

https://www.nanocom-diagnostics.com/

If you just want a cheap solution to your present problem, get a BECM sync-mate:

 

·
Registered
Joined
·
35 Posts
Discussion Starter #13
I have got the Faultmate MSV-2:


It has been out for quite a while, but on the p38 it still does more than any other system on the market.
The basic hardware is a reasonable price, but it is the cost of the software modules that adds up. You could start on a basic system that is locked to one VIN then add further modules if necessary in the future. It also needs to be connected to a PC with a serial port to get the best out of it.

Guys on here also speak highly of the Nanocom. You need to look at that as well:

https://www.nanocom-diagnostics.com/

If you just want a cheap solution to your present problem, get a BECM sync-mate:

Thank you, I'm getting a sync mate ordered and will look at getting one of the others as well.
I really appreciate your time and input.
 

·
Registered
Joined
·
1,292 Posts
Just reading reading your original post again. It will solve the engine sync problem but it won't get your keyfob working again. You will have to manually open and close the door with a key.

Each key fob has a unique fob code that is written in the BECM. You will have to read it your old BECM and enter it in the new one (this requires a Faultmate). Or get the original fob code from either a Main Dealer or Blackbox systems. Or get a set of locks from the same donor car as your replacement BECM.

Why was the original BECM replaced? They are pretty robust.
Most mechanics don't have a clue when it comes to p38's.
 

·
Registered
Joined
·
121 Posts
There is a vendor on ebay that sells so called "free-running" GEMS ECUs which are re-programmed to start the engine regardless of any silly codes communicated by BeCM or lack thereof. Fitting this ECU will enable you to fit an aftermarket remote for operating the door locks, and to effectively exorcise the troublesome immobilizer from the P38. Sadly, the equivalent is not yet available for Bosch/Thor V8.

If you are concerned about your truck getting stolen, there are plenty of modern solutions for securing the P38 that are infinitely superior to the original immobilizer in every respect. The electronics have come a long way since the early 1990s.
 

·
LEGACY VENDOR
Joined
·
4,157 Posts
I'm with Dave3d... why was the BECM actually replaced?? it could be that the issue isn't actually there, and it won't make a difference.

Was the BECM from another GEMs petrol? if so then the syncmate will get the GEMS ECU to relearn the new code from the BECM. If it wasn't from a GEMS, then you would need something like a Nanocom to tell the replacement BECM it is driving a GEMS ECU. The Motronic and Diesel engine ECU's have different immobiliser strategies,

It always worries me when people say the BECM has been changed, as it usually causes a whole load more headaches than getting the original one sorted!
 

·
Registered
Joined
·
35 Posts
Discussion Starter #17 (Edited)
Just reading reading your original post again. It will solve the engine sync problem but it won't get your keyfob working again. You will have to manually open and close the door with a key.

Each key fob has a unique fob code that is written in the BECM. You will have to read it your old BECM and enter it in the new one (this requires a Faultmate). Or get the original fob code from either a Main Dealer or Blackbox systems. Or get a set of locks from the same donor car as your replacement BECM.

Why was the original BECM replaced? They are pretty robust.
Most mechanics don't have a clue when it comes to p38's.
The problem originated with a dead battery and head gasket replacement. After jumping the rover the instrument cluster had all warning lights on as soon as the battery was connected but no gauge or LCD screen readings. All grounds, all of them were triple checked. The mechanic assumed they had broke a wire someplace so we replaced the engine loom. This did nothing to correct the problem.
With the new Petro gems becm the interior issues were resolved but the vehicle will not start. The mechanic believes they fried the old becm by jumping it too many times before battery replacement was done.
Is this possible?
As to the key fob, it was ireppairably damage when I bought it so I have always had to use the key to manually lock/unlock. The buttons were gone and the battery area had no contacts left in it. Its trashed.
The scynmate should be delivered this Tuesday so I am hoping it resolves the issue.
I do still have the old becm to get codes out of it if possible. Also, the passenger front door only locks/unlocks manually from inside the vehicle and this must be done to lock/unlock the rear gate.
Also, scanners are not communicating they the plug under the dash, 2 snap on scanners and another professional model was tried.
This p38 was seriously neglected before I bought it but ran good until the water pump failed damaging the head gasket. It only has 139,000 original on it.
I will get a faultmate soon hopefully, they arent cheap but I plan on having this diamond in the ruff a long time so it is worth it.
 

·
Registered
Joined
·
35 Posts
Discussion Starter #18
There is a vendor on ebay that sells so called "free-running" GEMS ECUs which are re-programmed to start the engine regardless of any silly codes communicated by BeCM or lack thereof. Fitting this ECU will enable you to fit an aftermarket remote for operating the door locks, and to effectively exorcise the troublesome immobilizer from the P38. Sadly, the equivalent is not yet available for Bosch/Thor V8.

If you are concerned about your truck getting stolen, there are plenty of modern solutions for securing the P38 that are infinitely superior to the original immobilizer in every respect. The electronics have come a long way since the early 1990s.
Thank you very much. I will look into these. Security isnt a huge issue for me. To my thinking simpler is better, to many electronic failures anymore. I would love to get away from all the headaches completely these modules create so this might be a great option.
Thank you
 

·
Registered
Joined
·
35 Posts
Discussion Starter #19
Syncmate worked. Now only problem is theres a gear box fault and it will not shift or engage sport mode.

Any ideas?
 

·
Registered
Joined
·
1,159 Posts
Gearbox Fault coming up as soon as you start the engine is usually a sign that the battery is low. If battery voltage drops below 10V at the gearbox ECU, it trips the message. So if the battery isn't good and the voltage drops when cranking, it will come up immediately. That puts the gearbox into limp mode so it uses only 3rd or 4th gear and Sport doesn't work. If it comes up when you are driving, then you have an actual gearbox fault which is also putting it into limp mode.
 
1 - 20 of 52 Posts
Top