I have just had some work done on the sky system, and shortly afterwards "protect" appeared on the Kenwood system, as all the sound comes thruogh it this has blocked it from working. Is there a common password to unblock the system? Thanks Andy

Pull the radio out, tape off all wires but yellow, red and black. Twist red/ yellow together and attach to positive 12 volt, attach black wire to negative 12 volts. Turn on radio and see if it comes out of protect mode. If it does, you will have to troubleshoot all of the speaker wires to find a short.

Hi there,

When the word PROTECT appears on this display, this means the unit has detected a critical fault which could potentially cause harm to your stereo system.

The most common cause is a short circuit somewhere - something even as simple as loose speaker wiring could cause a short, triggering the Protect message.

You will need to determine if there is a possible short somewhere, so I recommend you start by firstly turning power OFF, disconnecting all speaker wires, then turn unit back ON.

Operate the stereo (without speakers) and turn volume up:

• If Protect message appears when turning volume up, then stereo unit itself has an internal fault
• If no Protect message appears, then suspect the speakers may be causing the issue.
• Reduce volume and turn unit OFF

Re-connect speakers (ensure the connections are secure), turn unit ON:

• If turning volume up triggers the Protect message again, there is an issue with the speakers or connections

Hope this helps.....

Generally speaking, an amp attempts to protect itself from heat, shorts, overloads and operator exuberance by refusing to turn on or stay on.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech.

Check for loose speaker connections at the speaker as a root cause for intermittent shutdown.

It is not so easy to probe into to find a protection fault condition. The fault can be your output drivers- the mosfets fitted for both the channels,or a short in any of the primary circuits. Use a meter after disconnecting to check for short in the drivers. Disconnect the positive and negative voltages to the output and see if the protect changes.
Elimination of the circuits will determine the fault. If so replace the outputs. If not there can be issues in the mother board, maybe the protect circuit by itself is shutting off due to a faulty bias , maybe a leak in any voltage/current sensing circuit.Also disconnect the speakers and test, if the protect is off then check for short on the speakers.

You probably have a discrete component failing inside it.

Generally speaking, an amp protects itself from heat, shorts and overloads.

Overloads can be from excessive periods of high output and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced hands-on tech.

If protect is coming up on the display, it means the system is detecting a short somewhere on one of the speakers and so is turning the amp off to avoid damage.
Check all the connections at the back of the amp to ensure they are not shorting, and at the back of each speaker, if nothing is found there, check each wire for damage, or a bare wire touching the body of the car

If protect is coming up on the display, it means the system is detecting a short somewhere on one of the speakers and so is turning the amp off to avoid damage.
Check all the connections at the back of the amp to ensure they are not shorting, and at the back of each speaker, if nothing is found there, check each wire for damage, or a bare wire touching the body of the car

check the speaker wires are not shorting out

Here's the quote from the manual regarding "dcer": "The speaker wire has a short-circuit or touches the chassis of the vehicle and then the protection function is activated. Wire or insulate the speaker cable properly and press the reset button. If the "PROTECT/DCER" code does not disappear, consult your nearest service center "

I believe the manual can be downloaded from crutchfield .com after you go to the Kenwood KDC-138 page on their website. The reset button is either on the lower left of the face or, removing the face, on the lower left of the body. Hope this helps you.

The word PROTECT appears because there is a short. It can be in your speakers, try running it without the speakers plugged, or look if the wires arent shorting. If it stil ldoes that, its cause there is a short in it, from the output section. The system does that to prevent from damaging the electronic components inside.