The obd 2 scanner wont scan because its not receiving power from my truck (04 chevy trailblazer ) .where is the fuse that controls that circuit for the ecm

there are like 1billion cars noW doing this.

1. the gas cap was loose or bad !!!
2. theN the driver did not know it takes 30 driving cycles to clear the CEL lamp. OOPS 30? OBD2 DOES THAT. PER SERVICE MANUAL RULES, IF YOU READ THEM.
3. the fuse did not blow, or you'd have not asked where it is, I get that.!

99% of the time the cap was just loose or bad
my car the 1% time, the purge solenoid stuck
and my walmart silicon spray'd there (INSIDE IT) ended FAILURE for 50,000 more miles.
learn to buy AND USE a scan tool (borrow, rent ,buy)
tighten the cap again
scan the pCM see the cel lamp reasons./
push reset on the toll (CEL goes off if lucky and not 100 other DTC errors set)
and drive 3 times or more and the CEL stays off.

the other resets are(NO SCAN TOOL,. REALLY?)
1: PULL BATTERY LUG FOR 15MIN AND PUT BACK
OOPS RADIO GOES DEAD. dang
2: PULL ALL IOD FUSES. THE PCM MEMORY FUSE ONLY.
Ecm F29 IS IT(MEM) (PCM) 10AMPS
ALL DTCS NOW GONE, STORED. THE DATA FELL; INTO THE BIT BUCKET AS THEY SAY

IF ALL TESTS AND WILD GUESSING REPLACING ALL EVAP; VALVES. THEN COMES THE SMOKE MACHINE TESTS.
TO FIND THE LEAK
THIS IS AND EPA MANDATED MONITOR IN USA.
FOR SURE. THE 2 FUSES FOR BOTH EVAP VALVES ARE HERE.

Causes of code P1682 are similar on all GM products and could include one or more of the following-

• Failed, failing, or defective ignition switch (Most common)
• Defective fuses or fuse box. Note that under some conditions, such as when the vehicle had been parked in the sun, the fuse boxes on some models would deform, which often caused wiring connections in the fuse box to break or lose contact. This particular issue is known to affect Chevy Trailblazer, GMC Envoy, and Chevy SSR models
• Failed, defective, or malfunctioning PCM relays. Note that in cases where an ignition switch failure affected circuit 1, the reduced power feed to this relay often caused contacts in the relay to arc and burn
• Failed, defective, or malfunctioning fuel pumps, as the result of ignition switch failures affecting circuit 2
• Failed or failing PCM, but note that this code often mimics the effects of a failed PCM or corrupted software. Therefore, the fault must be sought elsewhere before any control module, including the PCM, is condemned

Ull need to scanit w a factorytool at a privateshop. It reads a datastream to pinpoint issues. Those portabl readers are general. Dont just replaceparts n hope. Oldercars can hav worn wireharness causin weird problms too. Unplug computer n cleanpins..dirt is common in aging vehicles creating issues. Since its jyst an emmission thing udont need to worry its runnin too lean or sumthin crucial

If this is an OBD scanning tool for automotive, there is a fuse that powers the OBD scanner jack. It is a 5 amp fuse and when it blows out, the scanner wont work. Check the fuse box

This is because there is no voltage on pin 16 in the DLC and so the scan tool cannot be powered ON. Most of the scanners have 12 VDC input port by which the scanner can be powered and the car can be scanned.

the obd 2 scanner power up at the 16 dlc terminal on the obd 1 type need cigarette lighter.

Gotta tell you, this question had me a little confused. Below are 2 wiring diagrams for you. One is for the cruise control circuit and the other is for the air conditioning circuit. The reason I gave you those is because it seems according to the wiring diagram in the cruise control that the fuse for the cruise control goes to the HVAC (air conditioning). According to the wiring diagram for the A/C yes that fuse also controls the ignition power for the A/C controller. In any case the fuse that would cover the cruise control is the number 30 fuse in the fuse panel located under the hood of the vehicle. Below is a picture of the location of the fuse panel and also fuse layout diagrams for the 6 cylinder and 8 cylinder engine vehicles as they have different layouts depending on the engine size. I hope this helps you and good luck.

You can check to see if you blew the cigarette lighter fuse by checking in the fuse box under the hood on the driver side. The fuse will be in the bottom right hand corner of the fuse box towards the windshield. If it lights up when test, the fuse is ok. What I found out on my '04 Tahoe was that in '03 GMC started making the CAN (Controller Area Network) which will not be compatible with plain OBD 2 Scanners & seem as though something is either wrong with the machine or car connector port. Believe me, I've taken my Tahoe to several auto parts store & even a few garages to be disappointed & not have my diagnosis done. Be sure that the OBD 2 Scanner you have, says "CAN" on it, or that it is "CAN" compatible & this will solve your issue.

Hi, a P0446 means Evaporative Emission Control System Vent Control Circuit Malfunction

Full details @ http://www.obd-codes.com/p0446

your underhood fuse block contains a fuse for the cigar lighter. this also powers the scan tool make sure it is not blown. chk pin 5 at data link connector for good ground pin 2 for power