Hey guys I'm getting this code on my 03 Sierra that I just bought.

P0719 Brake Switch Circuit Low Input

Cruise control does not work, and I can put it into gear without pushing the brake. Brake lights work fine.

I plugged a brand new GM switch in today, and I could still just drop it into gear. What else could it be?

Thanks

 

First thing's first... Clear the DTC. Read what I listed below, and click the hyperlinks at the bottom for a schematic and diag charts. Hope this helps!


CIRCUIT DESCRIPTION
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The brake switch indicates brake pedal status to the Powertrain Control Module (PCM) . The brake switch is a normally-closed switch that supplies battery voltage on circuit 420 to the PCM. Applying the brake pedal opens the switch, interrupting voltage to the PCM. When the brake pedal is released, the PCM receives a constant voltage signal. If the PCM receives a zero voltage signal at the brake switch input, and the Torque Converter Clutch (TCC) is engaged, the PCM de-energizes the TCC solenoid valve. The PCM disregards the brake switch input for TCC scheduling if there is a brake switch circuit fault (Refer to Diagnostic Aids).

When the PCM detects an open brake switch circuit (0 volts , low input) during accelerations, then DTC P0719 sets. DTC P0719 is a type C DTC.


CONDITIONS FOR RUNNING THE DTC
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No VSS assembly DTCs P0502 or P0503.
The ignition is ON.

CONDITIONS FOR SETTING THE DTC
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The PCM detects an open brake switch or circuit (0 volts ) for 15 minutes without changing for 2 seconds , and the following events occur seven times:


The vehicle speed is less than 8 km/h (5 mph) ;
then the vehicle speed is 8-32 km/h (5-20 mph) for 4 seconds ;
then the vehicle speed is greater than 32 km/h (20 mph) for 6 seconds .
ACTION TAKEN WHEN THE DTC SETS


The PCM does not illuminate the Malfunction Indicator Lamp (MIL) .
The PCM disregards the brake switch input for TCC scheduling.
The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records.
The PCM stores DTC P0719 in PCM history.


CONDITIONS FOR CLEARING THE DTC
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A scan tool can clear the DTC.
The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.
The PCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS
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Inspect the connectors at the PCM, the brake switch and all other circuit connecting points for an intermittent condition. Refer to Testing for Intermittent and Poor Connections in Diagrams.
Inspect the circuit wiring for an intermittent condition. Refer to Testing for Electrical Intermittents in Diagrams.
If the PCM detects a brake switch fault, then the brake switch input is disregarded for TCC scheduling. The PCM then uses throttle position and vehicle speed to determine TCC application and release. Use of these inputs may result in a noticeable harsh apply or abrupt release of the TCC.
Ask about the customer's driving habits. Ask about unusual driving conditions (e.g. stop and go, expressway, etc.).
Inspect the brake switch for proper mounting and operation.
Inspect for ABS DTCs. A faulty ABS condition may contribute to setting DTC P0719.

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Diag charts & a schematic:
Schematic
Diag Chart 1 of 2
Diag Chart 2 of 2

 

Thank you very much! I'll try that all tonight.

Jaxon

 

Well I didn't get too far into the test lighting and what not. I changed the brake switch, and pulled the code from the computer. Still can just grab the gearshifter and put it in gear. Didn't get to test the cruise control though.

 

i cleared mine and i never came back or set a light that i remember. I was just going through history codes on my truck on the tech II and it came up.

 

Well I've cleared mine three times, and it keeps coming up

 

hmm well you must have a problem mine just came on once.

 

In that case, I'd start looking at your fuses (check for shorts or bad fuses).

That switch has fused voltage leads. Start with your driverside fuse center, then check underhood.

 

ZR026T, I'm not sure exactly what your wanting me to do with the diagram? I've checked all the fuses, everything was good.

Thanks for the help!

Jaxon

 

Someone suggested to me that the remote starter could be causing this problem? Its tapped into the white wire on the brake switch.