Getting Code C1271
Thread Starter
Burning Brakes
Joined: Jun 2014
Posts: 799
Likes: 160
From: Landenberg PA
Getting Code C1271
Hi all, I have a 2000 vert, lately every so often I am getting the Service TCS/Services ABS messages, I check the DIC codes while car still running and have gotten C1271 (Master Cylinder Isolation Valve Malfunction). If I clear the code the warning lights go away.
Before I go nuts over the ECBM, I am thinking i may also have a battery/charging system issue. Admittedly I have not been driving the car very often and it has been sitting without the Battery Tender.
When I got the code the first time i put it the car on the charger, it took much longer than i am used to get to fully charged. In fact while charging above the 80% charge and opened the door, the charge would drop immediately.
Drove the car to work today, I had the Battery Voltage display on the DIC and it was reading 14.3 - 14.4 and even dropped to 13.8 or so when at idle at a red light.
Is it worth a charging system check before worrying about the ECBM? Is this an ECBM or Master Cylinder Issue if not a charging system issue?
Much Thanks.
Before I go nuts over the ECBM, I am thinking i may also have a battery/charging system issue. Admittedly I have not been driving the car very often and it has been sitting without the Battery Tender.
When I got the code the first time i put it the car on the charger, it took much longer than i am used to get to fully charged. In fact while charging above the 80% charge and opened the door, the charge would drop immediately.
Drove the car to work today, I had the Battery Voltage display on the DIC and it was reading 14.3 - 14.4 and even dropped to 13.8 or so when at idle at a red light.
Is it worth a charging system check before worrying about the ECBM? Is this an ECBM or Master Cylinder Issue if not a charging system issue?
Much Thanks.
Thread Starter
Burning Brakes
Joined: Jun 2014
Posts: 799
Likes: 160
From: Landenberg PA
I would start with the battery before getting into the charging system. I would definitely have the battery load tested. I would also measure the voltage across the battery posts using a digital multi meter. A good battery at full charge will measure 12.7 to 12.9 volts or more. Possibly your battery no longer wants to retain the charge after being fully charged.
Remember the dash gauges do NOT tell you the state of health of the battery. They tell you the state of health of the vehicle charging system. Limited amount that the charging system can do with a questionable battery..........
With engine running the dash gauges report the output voltage of the alternator. Engine OFF and key ON and the readings have no specific meaning because there are many vehicle electrical systems and/or aftermarket electrical additions that are loading the battery giving you an unknown meaning reading.
Remember the dash gauges do NOT tell you the state of health of the battery. They tell you the state of health of the vehicle charging system. Limited amount that the charging system can do with a questionable battery..........
With engine running the dash gauges report the output voltage of the alternator. Engine OFF and key ON and the readings have no specific meaning because there are many vehicle electrical systems and/or aftermarket electrical additions that are loading the battery giving you an unknown meaning reading.
Thread Starter
Burning Brakes
Joined: Jun 2014
Posts: 799
Likes: 160
From: Landenberg PA
Just quick update. Had the battery checked, no problem.
Since my last post I have been keeping the battery on a charger and although I have only driven the car a couple of times the code has not returned. Hoping it was a electrical glitch due to the car sitting w/o the battery charger being on. Will post if issue returns.
Since my last post I have been keeping the battery on a charger and although I have only driven the car a couple of times the code has not returned. Hoping it was a electrical glitch due to the car sitting w/o the battery charger being on. Will post if issue returns.
Tech Contributor
Joined: Oct 1999
Posts: 41,030
Likes: 9,782
From: Charlotte, NC (formerly Endicott, NY)
If the failure comes back the EBCM may not be the problem. There are other modules in the ABS circuit that need to be looked at and one of them could be a problem on a 17 year old car. The diagnostic in the FSM tells you to check a few things to make sure the failure isn't in the Brake Pressure Modulator Valve which is that thing with the pipes going to it the EBCM is fastened to.
I am attaching the diagnostic that should be followed by that code. You may have to do some work arounds if you don't have a Tech 2 but it is amazing what can be done by using a wire to apply volts or grounds where you need them or to gain access to pin so you can measure resistance or voltage at that pin. The resistance measurements may be critical because if they read less than infinite that could mean the solenoid in the BPMV is starting to short out.
Bill
I am attaching the diagnostic that should be followed by that code. You may have to do some work arounds if you don't have a Tech 2 but it is amazing what can be done by using a wire to apply volts or grounds where you need them or to gain access to pin so you can measure resistance or voltage at that pin. The resistance measurements may be critical because if they read less than infinite that could mean the solenoid in the BPMV is starting to short out.
Bill
Last edited by Bill Dearborn; Oct 12, 2016 at 12:22 PM.
Thread Starter
Burning Brakes
Joined: Jun 2014
Posts: 799
Likes: 160
From: Landenberg PA
If the failure comes back the EBCM may not be the problem. There are other modules in the ABS circuit that need to be looked at and one of them could be a problem on a 17 year old car. The diagnostic in the FSM tells you to check a few things to make sure the failure isn't in the Brake Pressure Modulator Valve which is that thing with the pipes going to it the EBCM is fastened to.
I am attaching the diagnostic that should be followed by that code. You may have to do some work arounds if you don't have a Tech 2 but it is amazing what can be done by using a wire to apply volts or grounds where you need them or to gain access to pin so you can measure resistance or voltage at that pin. The resistance measurements may be critical because if they read less than infinite that could mean the solenoid in the BPMV is starting to short out.
Bill
I am attaching the diagnostic that should be followed by that code. You may have to do some work arounds if you don't have a Tech 2 but it is amazing what can be done by using a wire to apply volts or grounds where you need them or to gain access to pin so you can measure resistance or voltage at that pin. The resistance measurements may be critical because if they read less than infinite that could mean the solenoid in the BPMV is starting to short out.
Bill
Tech Contributor
Joined: Oct 1999
Posts: 41,030
Likes: 9,782
From: Charlotte, NC (formerly Endicott, NY)
Thank You Bill, I greatly appreciate it. One thing I did not see the attachment you referred to. If easier you can send it to me email pcavall@verizon.net.
Bill
