My IS250 disabled by security/immobilizer system.
02-26-18, 04:24 PM
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IS250 Cannot Start - possibly disabled by immobilizer system
Hi.
I have a 2007 IS250 2wd that has been doing great the last few years until a month ago, when this immobilizing issue has occurred three times (this 3rd time, my car is permanently disabled). Basically, on my first encounter, one morning I stepped out to go to work, tried to unlock the car door with my key fob....strangely, the car wouldn't unlock. I had to pop out the cover and manually open the car door. I thought the battery was bad, but when I opened the hood and measured the voltage, it was 12.9v, which is fine. I got into the car and pressed the unlock button on the interior door panel to unlock all 4 doors, it wasn't responsive; in fact, many electronic buttons inside the car is unresponsive (ie. open trunk, fuel door, lock/unlock, etc) . Anyways, I stepped on the brake and pushed the start button, the car detects the key, the dashboard lights up and speedometer/tachymeter dial moves (as it normally does before cranking the engine); however, everything stops here; it acts as if I didn't step on the brake pedal and it doesn't even attempt to crank the engine (push start button was amber, not green). I shut down the acc, stepped outside and tried to reset the security with the key fob, it wasn't responsive. I cannot lock the doors (re-enable security) or unlock the doors (disable security) with the key fob.
Then out of ideas, I disconnected the battery cable and waited about 15 minutes. Luckily, when I plugged the battery cables back in, the car re-initiated and the engine started. It ran perfectly fine for a couple weeks, then the same issue happened again. I did the same thing (disconnected battery to reset ECU) and could successfully restart the car. I operated the car to work everyday for a few weeks until it occurred again this morning. I tried to disconnect the battery and plug it back in; however, this time around it didn't reset. To rule out any battery issues, I took the battery out of the car to charge it up fully and I also changed the battery in my key fob.
My troubleshoot findings:
1. Remote communicates (it could activate panic button), but is UNABLE to physically unlock or lock car, open truck (it does beep), etc. It's possible none of the actuators receive any power.
2. I can verify remote key code is sensed and cleared by security ECU (otherwise, it would report as "key not detected" and won't initiate ignition power).
3. When I press "unlock" on key fob, even though the door solenoids don't unlock, the side-mirror lights up, supposedly signaling that the security is disabled and car is ready to enter.
4. When I press "lock" on the key fob, the side-mirror lights shut off, signaling that the security is re-enabled.
5. No issues with main or exterior electrical power (dome light, dash lights, headlights, etc. are fully functional).
6. Upon inspection, interior electrical buttons / solenoids (lock/unlock, windows, side mirrors, trunk release, seats, radio, clock, etc) have no power and are non-functional.
7. Brake pedal remains stiff; cannot depress fully, no brake light (possibly no power to allow brake solenoid to release?); As a result, push-start button is always amber, not green.
8. Techstream showed DTC code P0504 (brake switch A/B correlation), but this error code is likely caused by #7 above.
9. I was able to override the issue a couple times by disconnecting battery cable to reset ECU, which shows this to be an electrical problem rather than physical.
I highly suspect something relating to the ECU/immobilization system is limiting the electrical power to the essential components in order for the car to start; however, I don't have much troubleshooting experience or equipment to go past my current findings. If you've encountered similar issues before or have more troubleshooting ideas, I would greatly appreciate your advice. Thank you.
I have a 2007 IS250 2wd that has been doing great the last few years until a month ago, when this immobilizing issue has occurred three times (this 3rd time, my car is permanently disabled). Basically, on my first encounter, one morning I stepped out to go to work, tried to unlock the car door with my key fob....strangely, the car wouldn't unlock. I had to pop out the cover and manually open the car door. I thought the battery was bad, but when I opened the hood and measured the voltage, it was 12.9v, which is fine. I got into the car and pressed the unlock button on the interior door panel to unlock all 4 doors, it wasn't responsive; in fact, many electronic buttons inside the car is unresponsive (ie. open trunk, fuel door, lock/unlock, etc) . Anyways, I stepped on the brake and pushed the start button, the car detects the key, the dashboard lights up and speedometer/tachymeter dial moves (as it normally does before cranking the engine); however, everything stops here; it acts as if I didn't step on the brake pedal and it doesn't even attempt to crank the engine (push start button was amber, not green). I shut down the acc, stepped outside and tried to reset the security with the key fob, it wasn't responsive. I cannot lock the doors (re-enable security) or unlock the doors (disable security) with the key fob.
Then out of ideas, I disconnected the battery cable and waited about 15 minutes. Luckily, when I plugged the battery cables back in, the car re-initiated and the engine started. It ran perfectly fine for a couple weeks, then the same issue happened again. I did the same thing (disconnected battery to reset ECU) and could successfully restart the car. I operated the car to work everyday for a few weeks until it occurred again this morning. I tried to disconnect the battery and plug it back in; however, this time around it didn't reset. To rule out any battery issues, I took the battery out of the car to charge it up fully and I also changed the battery in my key fob.
My troubleshoot findings:
1. Remote communicates (it could activate panic button), but is UNABLE to physically unlock or lock car, open truck (it does beep), etc. It's possible none of the actuators receive any power.
2. I can verify remote key code is sensed and cleared by security ECU (otherwise, it would report as "key not detected" and won't initiate ignition power).
3. When I press "unlock" on key fob, even though the door solenoids don't unlock, the side-mirror lights up, supposedly signaling that the security is disabled and car is ready to enter.
4. When I press "lock" on the key fob, the side-mirror lights shut off, signaling that the security is re-enabled.
5. No issues with main or exterior electrical power (dome light, dash lights, headlights, etc. are fully functional).
6. Upon inspection, interior electrical buttons / solenoids (lock/unlock, windows, side mirrors, trunk release, seats, radio, clock, etc) have no power and are non-functional.
7. Brake pedal remains stiff; cannot depress fully, no brake light (possibly no power to allow brake solenoid to release?); As a result, push-start button is always amber, not green.
8. Techstream showed DTC code P0504 (brake switch A/B correlation), but this error code is likely caused by #7 above.
9. I was able to override the issue a couple times by disconnecting battery cable to reset ECU, which shows this to be an electrical problem rather than physical.
I highly suspect something relating to the ECU/immobilization system is limiting the electrical power to the essential components in order for the car to start; however, I don't have much troubleshooting experience or equipment to go past my current findings. If you've encountered similar issues before or have more troubleshooting ideas, I would greatly appreciate your advice. Thank you.
Last edited by Beyondx4; 02-26-18 at 10:02 PM. Reason: Update on findings.
02-27-18, 07:55 AM
#2
First off.... the brake pedal. It will move if you put both feet into it. You will not harm it by pushing firmly. It is vacuum assist and when the engine runs it creates vacuum which offers mechanical assistance. Because the engine has not ran for bit, pushing the pedal has bled off the reserve of vacuum.
That said the car has multiple computers and your best bet is likely to buy a two day subscription to the TIS site and follow the troubleshooting guide there. You said you have access to Techstream. With a charger connected to the battery allow Techstream to run the full diagnostic sweep of all the computers. It may tell you something. This is very slow so your laptop better have a good battery and turn everything off in the car including the dome light.
Last little bit. You could go on a goose chase and inspect the main engine ECM, Body Control Module (BCM), and wireless MPX modules pins/connections. You're looking for discoloration, damage, growth from fluid intrusion.
It could a bad connection. I know a couple of the computers are behind the glove box so once the main ECM is inspected, look those over next.
Last little bit, with brake pedal mashed with both feet, hold Lexus logo on fob up to start button and push the button. What happens?
That's all I've got.
That said the car has multiple computers and your best bet is likely to buy a two day subscription to the TIS site and follow the troubleshooting guide there. You said you have access to Techstream. With a charger connected to the battery allow Techstream to run the full diagnostic sweep of all the computers. It may tell you something. This is very slow so your laptop better have a good battery and turn everything off in the car including the dome light.
Last little bit. You could go on a goose chase and inspect the main engine ECM, Body Control Module (BCM), and wireless MPX modules pins/connections. You're looking for discoloration, damage, growth from fluid intrusion.
It could a bad connection. I know a couple of the computers are behind the glove box so once the main ECM is inspected, look those over next.
Last little bit, with brake pedal mashed with both feet, hold Lexus logo on fob up to start button and push the button. What happens?
That's all I've got.
The following 2 users liked this post by 2013FSport:
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02-27-18, 09:43 PM
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Thanks....Finally diagnosed issue!
Dear 2013FSport,
Thank you for all your troubleshooting tips. I initially tried to put pressure on the brake pedal, but in the end, I just gave up. I was afraid of the more complicated issues you've mentioned (ECU, PCM, body modules, etc., which are all way above my head)! Fortunately, after troubleshooting the whole day yesterday, this morning I was able to confirm it had nothing to do with the ECU, security or immobilization system, but narrowed down the issue to the Fusible Link Block in the engine bay next to the battery (see attached picture). Here's how: This morning, before giving up, I attempted to check both fuse blocks under the dash and found out that there were zero electric coming into the cabin. From the outside, I checked for power with my multimeter in the fuse box in the engine bay. I probed on the bolt next to the fuse bar and got 0 volts. I then probed around the fusible link area a bit and heard a small spark, and it suddenly read 12.6 volts. I immediately went back into the car, turned on the ignition, depressed the brake pedal (the light turned green) then pushed the start button and the car started right up. Gosh...I was so happy!
Upon further inspection, it appears the fusible link has cracked and making inconsistent contact after years of vibrations (see attached picture). When I touched it with the multimeter probe to measure it, the metal points came into contact and allowed electricity back into the cabin, turning on the radio, switches, etc. All I had to do in order to reproduce the problem was to wiggle it a bit so it loses connection. The voltage at the bolt will then read 0v. Now that I was able to diagnose the root cause of the problem, it's time to learn how to replace this fusible link block. Thanks again for your response!
Thank you for all your troubleshooting tips. I initially tried to put pressure on the brake pedal, but in the end, I just gave up. I was afraid of the more complicated issues you've mentioned (ECU, PCM, body modules, etc., which are all way above my head)! Fortunately, after troubleshooting the whole day yesterday, this morning I was able to confirm it had nothing to do with the ECU, security or immobilization system, but narrowed down the issue to the Fusible Link Block in the engine bay next to the battery (see attached picture). Here's how: This morning, before giving up, I attempted to check both fuse blocks under the dash and found out that there were zero electric coming into the cabin. From the outside, I checked for power with my multimeter in the fuse box in the engine bay. I probed on the bolt next to the fuse bar and got 0 volts. I then probed around the fusible link area a bit and heard a small spark, and it suddenly read 12.6 volts. I immediately went back into the car, turned on the ignition, depressed the brake pedal (the light turned green) then pushed the start button and the car started right up. Gosh...I was so happy!
Upon further inspection, it appears the fusible link has cracked and making inconsistent contact after years of vibrations (see attached picture). When I touched it with the multimeter probe to measure it, the metal points came into contact and allowed electricity back into the cabin, turning on the radio, switches, etc. All I had to do in order to reproduce the problem was to wiggle it a bit so it loses connection. The voltage at the bolt will then read 0v. Now that I was able to diagnose the root cause of the problem, it's time to learn how to replace this fusible link block. Thanks again for your response!
02-28-18, 09:32 AM
#4
For some reason it seems people pop that section of the fusable link buss bar when doing the alternator swap.
How yours was hanging on by a thread is pretty strange. Glad you found it. There are a couple of DIY threads on swapping the that.
Keep us posted.
How yours was hanging on by a thread is pretty strange. Glad you found it. There are a couple of DIY threads on swapping the that.
Keep us posted.
06-25-22, 05:53 PM
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Help me??
Dear 2013FSport,
Thank you for all your troubleshooting tips. I initially tried to put pressure on the brake pedal, but in the end, I just gave up. I was afraid of the more complicated issues you've mentioned (ECU, PCM, body modules, etc., which are all way above my head)! Fortunately, after troubleshooting the whole day yesterday, this morning I was able to confirm it had nothing to do with the ECU, security or immobilization system, but narrowed down the issue to the Fusible Link Block in the engine bay next to the battery (see attached picture). Here's how: This morning, before giving up, I attempted to check both fuse blocks under the dash and found out that there were zero electric coming into the cabin. From the outside, I checked for power with my multimeter in the fuse box in the engine bay. I probed on the bolt next to the fuse bar and got 0 volts. I then probed around the fusible link area a bit and heard a small spark, and it suddenly read 12.6 volts. I immediately went back into the car, turned on the ignition, depressed the brake pedal (the light turned green) then pushed the start button and the car started right up. Gosh...I was so happy!
Upon further inspection, it appears the fusible link has cracked and making inconsistent contact after years of vibrations (see attached picture). When I touched it with the multimeter probe to measure it, the metal points came into contact and allowed electricity back into the cabin, turning on the radio, switches, etc. All I had to do in order to reproduce the problem was to wiggle it a bit so it loses connection. The voltage at the bolt will then read 0v. Now that I was able to diagnose the root cause of the problem, it's time to learn how to replace this fusible link block. Thanks again for your response!
Thank you for all your troubleshooting tips. I initially tried to put pressure on the brake pedal, but in the end, I just gave up. I was afraid of the more complicated issues you've mentioned (ECU, PCM, body modules, etc., which are all way above my head)! Fortunately, after troubleshooting the whole day yesterday, this morning I was able to confirm it had nothing to do with the ECU, security or immobilization system, but narrowed down the issue to the Fusible Link Block in the engine bay next to the battery (see attached picture). Here's how: This morning, before giving up, I attempted to check both fuse blocks under the dash and found out that there were zero electric coming into the cabin. From the outside, I checked for power with my multimeter in the fuse box in the engine bay. I probed on the bolt next to the fuse bar and got 0 volts. I then probed around the fusible link area a bit and heard a small spark, and it suddenly read 12.6 volts. I immediately went back into the car, turned on the ignition, depressed the brake pedal (the light turned green) then pushed the start button and the car started right up. Gosh...I was so happy!
Upon further inspection, it appears the fusible link has cracked and making inconsistent contact after years of vibrations (see attached picture). When I touched it with the multimeter probe to measure it, the metal points came into contact and allowed electricity back into the cabin, turning on the radio, switches, etc. All I had to do in order to reproduce the problem was to wiggle it a bit so it loses connection. The voltage at the bolt will then read 0v. Now that I was able to diagnose the root cause of the problem, it's time to learn how to replace this fusible link block. Thanks again for your response!
12-29-23, 12:39 PM
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I know what it is
So I had the same problem with my car after the battery was disconnected and what it was is. It's going to sound really stupid and simple but so what you want to do is get out of your car. Lock it either with the key or the key fob and let it sit for 5 minutes. Go back to it and before you open the door, stick your key in the door hole. Twist it left. You want to unlock it three times so you unlock it then you lock it. Unlock it, lock it. Unlock it and then once you get back in the car it should start right up. It was doing the same thing. Made the battery drain. It seem like the battery was draining and stuff but it wasn't. It was the security system since the battery was removed. Try it if this is still something that you
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