Brake sensor issues
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Brake sensor issues
I have a 2011 F150 eco with 80k on it. Recently the front brakes and rotors where getting pretty bad, but right before I replaced them the advanced tractor, brake light, abs lit up. I scanned the truck and got a C1140 brake pressure sensor signal failure. I replaced the master cyl with a used one thinking it was a sensor issue. That did not help. I checked all the fuses and nothing blown.
any thoughts?
any thoughts?
Hotshot
Joined: Jan 2004
Posts: 19,736
Likes: 1,069
From: St Louis
The factory service manual does not have a "C1140" listed as a supported DTC for the ABS system. Verify the fault code.
If you have a C1440 DTC, that sensor is integrated into the HCU, it is not part of the master cylinder. It is highly recommended to follow the established diagnostic procedure to prevent the unnecessary replacement of parts when "guessing" wrongly.
If you have a C1440 DTC, that sensor is integrated into the HCU, it is not part of the master cylinder. It is highly recommended to follow the established diagnostic procedure to prevent the unnecessary replacement of parts when "guessing" wrongly.
Thread Starter
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New User
Joined: Oct 2011
Posts: 4
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The factory service manual does not have a "C1140" listed as a supported DTC for the ABS system. Verify the fault code.
If you have a C1440 DTC, that sensor is integrated into the HCU, it is not part of the master cylinder. It is highly recommended to follow the established diagnostic procedure to prevent the unnecessary replacement of parts when "guessing" wrongly.
If you have a C1440 DTC, that sensor is integrated into the HCU, it is not part of the master cylinder. It is highly recommended to follow the established diagnostic procedure to prevent the unnecessary replacement of parts when "guessing" wrongly.
I don’t have a factory service manual so I will have to get one, so I can follow the diagnostic procedure
Hotshot
Joined: Jan 2004
Posts: 19,736
Likes: 1,069
From: St Louis
Follows.... Sorry, formatting is a bit jacked up. I'll see if I can clean it up manually. None of the hyperlinks will work, can't fix that.
Pinpoint Test G: DTCs C116A, C1440
Refer to Wiring Diagrams Cell 42 ,
Vehicle Dynamic Systems for schematic and connector information.
Normal OperationThe pressure transducer is integral to the Hydraulic Control Unit (HCU). The pressure transducer sends a signal to the ABS module that varies in relation to the amount of pressure applied to the brake pedal. The more pressure applied, the greater the signal sent to the ABS module. If a new pressure transducer is needed, then a new HCU must be installed.
When the brake pedal is pressed, the stoplamp switch closes and voltage is sent to the PCM. The PCM then sends a message over the High Speed Controller Area Network (HS-CAN) to the ABS module indicating the brake pedal has been pressed. DTCs set in the ignition cycle can only be cleared by cycling the ignition off and on once the fault has been corrected.
Test Step Result / Action to Take
G1 INSPECT THE STOPLAMP SWITCH AND VERIFY INSTALLATION
GO to G2 .
No
If the stoplamp switch is damaged, INSTALL a new stoplamp switch. REFER to Stoplamp Switch Removal and Installation in Section 417-01 . DIAGNOSE the stoplamps. REFER to Stoplamp Switch Diagnosis and Testing in Section 417-01 .
G2 MONITOR THE ABS MODULE BRAKE ON/OFF (BOO_ABS) PID
GO to G4 .
No
GO to G3 .
G3 MONITOR THE PCM BRAKE ON/OFF (BOO1) PID
REFER to Section 418-00 to continue diagnosis of the HS-CAN .
No
REFER to Section 417-01 to continue diagnosis of the stoplamp switch fault.
G4 MONITOR THE INITIAL (BRAKE PEDAL NOT APPLIED) BRAKE PRESSURE USING THE ABS MODULE BRAKE PRESSURE (BRAKPRES) PID
GO to G5 .
No
INSTALL a new HCU . REFER to Hydraulic Control Unit (HCU) in this section.
G5 MONITOR THE BRAKPRES PID WHILE APPLYING THE BRAKE PEDAL
The system is operating correctly at this time. The concern may have been caused by an incorrectly installed stoplamp switch.
No
INSTALL a new HCU . REFER to Hydraulic Control Unit (HCU) in this section.
Refer to Wiring Diagrams Cell 42 ,
Vehicle Dynamic Systems for schematic and connector information.
Normal OperationThe pressure transducer is integral to the Hydraulic Control Unit (HCU). The pressure transducer sends a signal to the ABS module that varies in relation to the amount of pressure applied to the brake pedal. The more pressure applied, the greater the signal sent to the ABS module. If a new pressure transducer is needed, then a new HCU must be installed.
When the brake pedal is pressed, the stoplamp switch closes and voltage is sent to the PCM. The PCM then sends a message over the High Speed Controller Area Network (HS-CAN) to the ABS module indicating the brake pedal has been pressed. DTCs set in the ignition cycle can only be cleared by cycling the ignition off and on once the fault has been corrected.
- DTC C116A (ABS Pressure Transducer / Brake Switch Mismatch) — this DTC sets in every ignition cycle if, during normal operation, the stoplamp switch message does not match the HCU transducer, both signals have to agree about whether the brakes are being applied or not.
- DTC C1440 (Pressure Transducer Main/Primary Signal Faulted) — this DTC sets in every ignition cycle if the signal the pressure transducer sends to the ABS module does not agree with the stoplamp switch position.
- This pinpoint test is intended to diagnose the following:
- Network communication concern
- Stoplamp switch
- HCU
PINPOINT TEST G: DTCs C116A, C1440
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.Test Step Result / Action to Take
G1 INSPECT THE STOPLAMP SWITCH AND VERIFY INSTALLATION
- Inspect the stoplamp switch for obvious signs of damage.
- Remove and install the stoplamp switch. Refer to Stoplamp Switch Removal and Installation in Section 417-01 .
- Press the brake pedal and verify the stoplamps operate correctly.
- Do the stoplamps operate correctly and is the switch free from any damage?
GO to G2 .
No
If the stoplamp switch is damaged, INSTALL a new stoplamp switch. REFER to Stoplamp Switch Removal and Installation in Section 417-01 . DIAGNOSE the stoplamps. REFER to Stoplamp Switch Diagnosis and Testing in Section 417-01 .
G2 MONITOR THE ABS MODULE BRAKE ON/OFF (BOO_ABS) PID
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger — ABS Module .
- Press and release the brake pedal while monitoring the BOO_ABS PID.
- Does the PID display ON with the brake pedal applied and OFF with the brake pedal released?
GO to G4 .
No
GO to G3 .
G3 MONITOR THE PCM BRAKE ON/OFF (BOO1) PID
- Enter the following diagnostic mode on the scan tool: DataLogger — PCM .
- Press and release the brake pedal while monitoring the BOO1 PID.
- Does the PID display ON with the brake pedal applied and OFF with the brake pedal released?
REFER to Section 418-00 to continue diagnosis of the HS-CAN .
No
REFER to Section 417-01 to continue diagnosis of the stoplamp switch fault.
G4 MONITOR THE INITIAL (BRAKE PEDAL NOT APPLIED) BRAKE PRESSURE USING THE ABS MODULE BRAKE PRESSURE (BRAKPRES) PID
- Enter the following diagnostic mode on the scan tool: DataLogger — ABS Module .
- With the brake pedal not applied, record the pressure displayed by the BRAKPRES PID.
- Is the initial brake pressure less than 275 kPa (40 psi) with the brake pedal not applied?
GO to G5 .
No
INSTALL a new HCU . REFER to Hydraulic Control Unit (HCU) in this section.
G5 MONITOR THE BRAKPRES PID WHILE APPLYING THE BRAKE PEDAL
- Enter the following diagnostic mode on the scan tool: DataLogger — ABS Module .
- Firmly press and release the brake pedal while monitoring the BRAKPRES PID.
- Does the PID increase with firm pressure on the brake pedal and then decrease with the brake pedal released?
The system is operating correctly at this time. The concern may have been caused by an incorrectly installed stoplamp switch.
No
INSTALL a new HCU . REFER to Hydraulic Control Unit (HCU) in this section.
Freshman User
Joined: Sep 2004
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Apology's for hitting an old thread. 2012 F150, 4x4. 5.0 62k was sitting for a few weeks then on first drive threw a C116a and a C1440 that is persisting. What do you think my chances of fixing this would be if I found a used HCU with the same PN and just swapped out the pump portion keeping the original module. Everything I've read says the pressure transducer is in the pump portion. Thanks!
Mountain Pass
Joined: Feb 2010
Posts: 140
Likes: 17
From: Brantford Ontario
For what little I know if replacing the HCU it still has to be married computor wise to your truck...No way around it....
I believe you can do it with forscan if not wanting to spend stealer-ship monies...
There a definite procedure you have to follow to replace the unit.....
Some one else will probably will point you in the right direction ??
I believe you can do it with forscan if not wanting to spend stealer-ship monies...
There a definite procedure you have to follow to replace the unit.....
Some one else will probably will point you in the right direction ??
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