P38A Brake light is permanently on

pwood999 · 2025-03-08T13:18:36+0000

@Frank_38 You didn't say if it's the Brake Lights on the back of the car or Brake Warning on dash ?

ABS & TC are nothing to do with the brake light switch. ABS needs the pump to run & pressurise the system, hence the questions above about pumping the pedal & waiting for the pump to engage.

Nanocom will show you the state of the brake pedal switch, and also why the other lights are on.

From RAVE:
The Anti–Lock Brake System ECU (Z108) also has
diagnostic capabilities that allow it to detect faults
that may impair the system’s efficiency. If a fault
occurs, the ECU informs the operator of a problem
by illuminating the ABS or the ETC warning light.
The ECU also illuminates the warning light when the
ignition is first placed in position II. The ABS warning
light will remain illuminated until the ECU completes
a self check of the system. When the ECU sees all
wheels reach a speed of 7 km/h (5 mph), the self
check is completed and the ABS warning light turns
off. If a fault is detected during the self check, the
ABS or the ETC warning light will remain on and a
fault code will be stored in memory to aid in servicing
the system. When an ABS fault has been detected,
the message ABS FAULT may also display.
The fault code can be retrieved using a diagnostic
tester.

Frank_38 · 2025-03-08T14:13:29+0000

ok, I drove again. I can hear the pump every time I press the brakes - really every time.

And even when shifting into gear - but maybe I'm imagining it?

Frank_38 · 2025-03-08T14:28:01+0000

pwood999 said:
@Frank_38 You didn't say if it's the Brake Lights on the back of the car or Brake Warning on dash ?

ABS & TC are nothing to do with the brake light switch. ABS needs the pump to run & pressurise the system, hence the questions above about pumping the pedal & waiting for the pump to engage.

Nanocom will show you the state of the brake pedal switch, and also why the other lights are on.

From RAVE:
The Anti–Lock Brake System ECU (Z108) also has
diagnostic capabilities that allow it to detect faults
that may impair the system’s efficiency. If a fault
occurs, the ECU informs the operator of a problem
by illuminating the ABS or the ETC warning light.
The ECU also illuminates the warning light when the
ignition is first placed in position II. The ABS warning
light will remain illuminated until the ECU completes
a self check of the system. When the ECU sees all
wheels reach a speed of 7 km/h (5 mph), the self
check is completed and the ABS warning light turns
off. If a fault is detected during the self check, the
ABS or the ETC warning light will remain on and a
fault code will be stored in memory to aid in servicing
the system. When an ABS fault has been detected,
the message ABS FAULT may also display.
The fault code can be retrieved using a diagnostic
tester.

...Brake Lights on the back of the car

Frank_38 · 2025-03-08T15:11:06+0000

I found something here from 2016:

"If it runs every 2-3 pedal pushes, it is tired.....if it runs on each press of the pedal, the accumulator is finished and needs to be replaced....you MUST use the RAVE method of de-pressurising the Accumulator before removal."

P38A - ABS & Traction Control Fault (2001 P38 4.0)

Hi everyone, I need some help. I've just got my P38 back from a "landrover specialist" after over 3 months, long story, but they were changed the wheel bearings and fixed the head gasket, but buggered the electrics and ended removing my LPG system along the way. Anyway, now its showing ABS...

www.landyzone.co.uk

which "the accumulator"?

in my case, the pump starts every time the brake is pressed.

pwood999 · 2025-03-08T15:54:17+0000

Yes, you have two issues. Brake lights on rear will either be the switch, or a BECM issue. Most likely the switch.

Before you replace the Accumulator, check pump is fully pressurising.

With car stationary wait for the pump to stop running. Then drive forward until you're over 5mph (without using brakes), and the lights should go off. ABS ECU needs to see wheels moving or the lights stay on.

If that works, then you just need a new accumulator. If the pump doesn't stop running, then either the pump or pressure switch is bad.

Datatek · 2025-03-08T16:01:26+0000

The accumulator is the ball shaped lump on top of the pump.

Frank_38 · 2025-03-09T11:51:03+0000

pwood999 said:
Yes, you have two issues. Brake lights on rear will either be the switch, or a BECM issue. Most likely the switch.

Before you replace the Accumulator, check pump is fully pressurising.

With car stationary wait for the pump to stop running. Then drive forward until you're over 5mph (without using brakes), and the lights should go off. ABS ECU needs to see wheels moving or the lights stay on.

If that works, then you just need a new accumulator. If the pump doesn't stop running, then either the pump or pressure switch is bad.

...the lights don't go out.
Started the engine, waited until the pump goes out (slight buzzing stops). Then drove off for a long time without braking - nothing happens, the TC and ABS lights stay on.

Could it be that I have destroyed it by stepping too hard on the brakes?
When I changed the switch, I stepped very hard on the brakes 2-3 times - the engine was off.

P38A Brake light is permanently on

pwood999

Well-Known Member

Frank_38

Member

Frank_38

Member

Frank_38

Member

P38A - ABS & Traction Control Fault (2001 P38 4.0)

pwood999

Well-Known Member

Datatek

Well-Known Member

Frank_38

Member

Similar threads