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2001 chevy silverado 1500: the check engine light is on it

Resolved Question:

hi i have a problem with a 2001 chevy siverado 1500 4.8lt the check engine light is on it has 1 code p0453
Submitted: 3 years ago.
Category: Chevy
Expert:  Neal replied 3 years ago.
Here is the info on that and some steps you can take to resolve it or you can pass this info on to your mechanic. The good news is that it is not a major issue and there is no harm in driving it until it is fixed.

P0453 - Evaporative Emissions Control System Pressure Sensor High Input
What does that mean?

The EVAP (Evaporative Emissions) System allows fuel tank vapors to be purged into the engine and burnt rather than expelled into the atmosphere as harmful emissions. The EVAP system contains a pressure sensor to check the integrity of the system. Periodically, the EVAP system performs a pressure test to check that there are no leaks in the system. It uses this sensor, also known as a fuel tank pressure (FTP) sensor to check for leaks. Basically P0453 means the PCM (Powertrain Control Module) noticed the EVAP Pressure sensor or FTP is indicating a higher than normal pressure (above 4.5 Volts) in the EVAP system. NOTE: On some vehicles the FTP is a part of the fuel pump assembly in the tank.

Potential Symptoms

There will likely be no noticeable symptoms along with this code other than the MIL (Malfunction Indicator Lamp), commonly known as Check Engine Light illumination. However, there may be noticeable fuel odors in some cases.

Causes

A P0453 DTC trouble code may be caused by one or more of the following:

Open on FTP sensor signal wire
Short to voltage on FTP sensor signal wire
Bad FTP sensor
Abnormally high pressure in fuel tank due to blockage in EVAP purge hoses or overfilled tank
Loose/damaged FTP sensor connector
Loss of ground to the sensor
Possible Solutions

Using an scan tool access FTP sensor value with Key on Engine off (KOEO). Normal value is usually somewhere near 2.5 Volts at atmospheric pressure (may fluctuate some due to altitude). It shouldn't ever be above 4.5 Volts.

1) If it is close to 2.7V with the gas cap off, the problem is likely intermittent. Using a Digital Volt Ohm Meter, measure the voltage on the signal wire while trying to induce the problem by wiggle testing all the wiring at the FTP sensor. If the voltage fluctuates when wiggle testing, check for connector problems; i.e. water in the connector, broken or chafed wiring.

2) If the value shown on the scan tool is above 4.5V, unplug the sensor (if possible) and check for voltage again. If the high voltage is still present when unplugged, inspect wiring harness for a short to voltage on the signal wire. If the high voltage disappears when unplugging the sensor, check for a good ground to the sensor and proper reference voltage. If you have a good ground and 5 Volts reference voltage, replace the FTP sensor since it's likely shorted out.
Neal, Chevy Mechanic
Category: Chevy
Satisfied Customers: 8337
Experience: Shop Owner and Mechanic on multiple makes.
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