P 4020 - JBL Car Audio User Guide / Operation Manual. Page 7

7

No audio

Low/no remote on voltage

Check connections; turn-test turn-on voltage

Speakers are not connected or are blown

Check wiring; use VOM/DVM to measure speaker-coil 
resistance

Distorted audio

Input sensitivity is not set properly

See Setting Input Sensitivity on page 5

Audio lacks “punch”

Speakers are wired with wrong polarity

Check polarity of connections; refer to Applications

Audio cycles off and on;

A protection circuit is turning the 

Verify the following: off electrical system is

amber protection LED 

amplifier off and on

between 5 ~ 18Vdc; temperature is not 

(JBL badge on top panel)

over 194°F (90°C); there are no short circuits; speaker 

is flashing

loads are not less than 2 ohms (4 ohms in mono)

Audio cycles off and on;

GAIN is set too high

Set Input Sensitivity

amber protection LED

correctly (see page 5)

(on top panel) is flashing

Fuse blows

Incorrect wiring or short circuit

Check connections; refer to Applications 

Use the following guide to identify
symptoms and solve problems. Make
sure the vehicle’s electrical system is
working properly and power is reaching
the JBL P-4020 (or P-4040).

Declaration of Conformity

Kongevejen 194B 
DK-3460 Birkerød
DENMARK

declare in own responsibility, that the products  

  described

in this owner’s manual are in compliance with technical

 

standards:

EN
EN 

55013/A12/8.1994
55020/12.1994

Steen Michaelsen

Birkerød. DENMARK. 3/98

P-4020/4040 OM.  7/14/98 11:42 AM  Page 7