Question about Cars & Trucks
Check engine light
Posted by Anonymous on
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Posted on Jan 02, 2017
SOURCE: obd1 scan tool will notaccess
A couple of ways to check and see if the computer is ok first:
check engine light must come onwith they in on position
The fuel pump must run for two (2) seconds with the key ON
There must be a 5 volt reference at sensors like map, TPS
Must communicate with scan tool
The ORANGE wires at the computer are you power input wires one has 12V all the time this is your KEEP ALIVE MEMORY
one is 12 with the Key on you MUAT HAVE VOLTAGE AT BOTH
Check the computers Ground most are out under the hood and are brown wires
Try the GM TAP TEST this is a factory authorized test with the computer connected and you verified all of the above SLAP the computer with the open hand firmly not too hard but firm see if anything changes,
Do not disconnect the battery you will erase all the codes!
Please contact me if you need any additional information.
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Posted on Aug 14, 2008
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
Posted on Nov 15, 2009
This might help you to better understand the EVAP system and help diagnosing the code that was set. Basically there is a leak and you need to find it. Could be very hard to find without a smoke machine. I would take it into a shop to have it tested with a smoke machine and go from there. Some people might say to just replace the gas cap, but if that's not what it is, there is $20-30 wasted, when it could have been put towards an actual diagnoses that will actually help you to fix the problem
DTC P0455 System Description
The control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge solenoid valve OPEN and the EVAP canister vent solenoid valve CLOSED . This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge solenoid valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, this DTC sets. Hope i didn't confuse you.
Posted on Feb 02, 2010
A 1993 Tracker will have OBD1 technology. Just unplug the battery for 5minutes and plug it back in. If the light persists You will have to find out and repair the problem that your cars computer believes it has.
Posted on May 12, 2010
Tips for a great answer:
Jun 15, 2016 | 2008 Honda Accord
The ability of the control modules to communicate through the serial data circuit.
The identification of any stored diagnostic trouble codes (DTCs) and their status.
The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.
Diagnostic System Check - Engine Electrical
The numbers below refer to the step numbers on the diagnostic table.
Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
The symptom list in Symptoms will determine the correct diagnostic procedure to use.
The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
Did you perform the Battery Inspection/Test?
Go to Step 2
Go to Battery Inspection/Test
Install a scan tool.
Does the scan tool power up?
Go to Step 4
Go to Scan Tool Does Not Power Up in Data Link Communications
Important: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.
Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool.
Rotate the ignition switch through all positions while observing the Class 2 Power Mode on the Scan Tool. Refer to the Serial Data Power Mode table within the Body Control System Description and Operation in Body Control System for a list of the power mode states that correspond to each ignition switch position.
Does the Class 2 Power Mode parameter reading match the ignition switch position for all the selected positions?
Go to Step 4
Go to Power Mode Mismatch in Body Control System
Turn ON the ignition, with the engine OFF.
Attempt to communicate with each module on the class 2 serial data circuit:
• The body control module (BCM)
• The driver information center (DIC)
• The instrument panel cluster (IPC)
• The powertrain control module (PCM)
Does the scan tool communicate with any module on the class 2 serial data circuit?
Go to Step 5
Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications
Select the Display DTCs function for each module. If using a Tech 2, use the Class 2 DTC Check feature in order to determine which modules have DTCs set.
Record all of the displayed DTCs the DTC status and the module which set the DTC.
Does the scan tool display any DTCs?
Go to Step 6
Go to Symptoms - Engine Electrical
Does the scan tool display any DTC beginning with "U"?
Go to Diagnostic Trouble Code (DTC) List in Data Link Communications
Go to Step 7
Does the scan tool display any DTC beginning with "B"?
Go to Diagnostic Trouble Code (DTC) List in Body Control Systems
Go to Diagnostic Trouble Code (DTC)
Oct 28, 2015 | Cars & Trucks
The powertrain control module (PCM)
The instrument panel cluster
The sensing diagnostic module (SDM)
The electronic brake control module (EBCM)
The serial data line class 2 (circuit 1807) allows the scan tool to access directly the PCM in order to read emissions-related information. The scan tool gains access to both data lines through the data link connector (DLC). You may then monitor or control system operations for diagnostic purposes.
Mar 08, 2015 | 1999 Pontiac Sunfire
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