hey everyone truck popped a code today 0540 what is it





Craig

Occasionally, vehicle manufacturers will use the same DTC across different vehicles and platforms. If the DTC that you entered above returns more than one DTC description below, you will need to match certain digits of your VIN to determine which DTC description applies to your vehicle.
For example:You have a General Motors vehicle and the Diagnostic Trouble Code is B0566.
<UL>
<LI>If the third digit in your VIN is a "1", your DTC means Infl Rest System Indicator Circuit Malf.
<LI>If the third digit is a "2", the DTC means Temp. Gage Data Out of Range </LI>[/list]
<HR id=StartList width="100%" color=#000000 SIZE=2>

<TABLE width="100%" align=center border=1>
<T>
<TR>
<TD rowSpan=2>DTC</TD>
<TD rowSpan=2>Description</TD>
<TD align=middle colSpan=6>VIN Digits</TD></TR>
<TR>
<TD align=middle>2
Manufacturer</TD>
<TD align=middle>3
Division</TD>
<TD align=middle>4
Body</TD>
<TD align=middle>5
Series</TD>
<TD align=middle>8
Engine</TD>
<TD align=middle>10
Year</TD></TR>
<TR>
<TD vAlign=top>P0540</TD>
<TD vAlign=top>Intake Air Heater "A" Circuit</TD>
<TD vAlign=top align=middle colSpan=6>Generic OBDII Code </TD></TR></T></TABLE>

Thanks





Craig

CIRCUIT DESCRIPTION
The engine control module (ECM) uses an intake air heater (http://library.motoralldata.com/alldata/MTRLIB~C36280~R0~OD~N/0/86372027/86372028/86372041/87577232/34853741/34857029/34858641/34859414) (IAH) to warm the incoming air for proper cylinder combustion. The ECM (http://library.motoralldata.com/alldata/MTRLIB~C36280~R0~OD~N/0/86372027/86372028/86372041/87577232/34853741/34857029/34857030/34857300) grounds the control coil of the IAH relay to energize the heater during cold operation. If the ECM detects voltage on the IAH circuit when the relay is commanded OFF, or incorrect voltage when the relay is commanded ON, a DTC will set.

CONDITIONS FOR RUNNING THE DTC

<UL =disc>
<LI>The battery voltage is between 10-18 volts .
<LI>The intake air temperature (IAT) is less than 23°C (73°F) with the engine running.</LI>[/list]


OR


<UL =disc>
<LI>The coolant temperature is less than 49°C (121°F) with the ignition ON, engine OFF for more than 3 seconds .</LI>[/list]


CONDITIONS FOR SETTING THE DTC
The heater line voltage is more than 8.1 volts with the relay OFF.

OR

The heater line voltage is between 3.8-8.1 volts with the ignition OFF.

AND

The heater line voltage is less than 0.5 volt below battery voltage with the ignition ON.

OR

The heater line voltage is less than 3.8 volts with the relay OFF.

AND

The reference line voltage is low with the relay OFF.

ACTION TAKEN WHEN THE DTC SETS