P0452

[dlstewart01]

Started the 2005 GMC this morning and the fuel gage did not work and a low fuel message came on. When I parked it last night it had a half tank of fuel. The check engine light was also on.

 

I pulled the code and it came up P0452. Thats for a fuel tank pressure sensor. The truck runs normal. I drove it for about 5 miles with no issues.

 

I have not got into it yet but since the fuel gage is not working as well do you think I need the fuel pump/sending unit or just the pressure sensor? The pressure sensor is mounted on the pump unit.

 

Could be a wiring/ ground problem. I think both of them may share some same wiring. What do the experts say.

[jaredlucky16]

Put a GM fuel pump module in it

[gmtech4]

get it diagnosed FIRST !!!!!!!!

[dlstewart01]

Put a GM fuel pump module in it

 

 

It has the original fuel pump on it and it works perfect. There is a problem with the fuel tank presure sensor and the fuel gage that showed up together.

 

Before someone brings it up, I have an extra cluster that I know the fuel gage works. I will swap them out to rule out a bad stepper motor. I was just wondering if some one else has had this problem.

 

Thanks

[dlstewart01]

The code pulled is PO452...fuel tank pressure sensor. The local dealer told me to replace the sensor. He said the fuel gage was a seperate matter. i don't think so. I could be wrong but I don't think so.

[gmtech4]

did they diagnose it or scan it in the drivethru ? i could run the code for you if you want

[dlstewart01]

I scanned it. I just ran it by their tech to get his opinion.

 

I may have to get a diagnosis. I was trying to save a buck. I am retired and don't have to drive it every day so I got time.

[gmtech4]

you then have a decision to make ....good luck ...

[dlstewart01]

http://www.ls2.com/boggs/dtcs/DTC%20P0452.htm

[gmtech4]

im adding the code ,its hard to figure out the diag trouble tree at the bottom ,,answer to yes is first then no is second ,,it then sends you to another line,,,a scanner is needed of course but a little info doesn't hurt ,,,,PM me if ya want ,i can explain it further or a phone call ...i want to help bud as the possibilities can be disastrous financially if the wrong part is installed as you can see in the tree,,

 

 

DTC P0452

 

Circuit Description

 

The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the evaporative emission (EVAP) system, and the outside air pressure. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage goes below a calibrated value, this DTC sets.

The following table illustrates the relationship between the FTP sensor signal voltage and the EVAP system pressure/vacuum.

 

FTP Sensor Signal Voltage

 

 

 

Fuel Tank Pressure

 

 

 

High, Approximately 1.5 Volts or More

 

 

Negative Pressure/Vacuum

 

 

Low, Approximately 1.5 Volts or Less

 

 

Positive Pressure

 

DTC Descriptor

 

This diagnostic procedure supports the following DTC:

DTC?P0452 Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage

Conditions for Running the DTC

 

 

• The engine is running.

 

 

 

• DTC?P0452 runs continuously once the above condition is met.

 

Conditions for Setting the DTC

 

 

• The FTP sensor voltage is less than 0.1?volts.

 

 

 

• All conditions are present for more than 5?seconds.

 

Action Taken When the DTC Sets

 

 

• The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.

 

 

 

• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

 

Conditions for Clearing the MIL/DTC

 

 

• The control module turns OFF the malfunction indicator lamp (MIL) after 3?consecutive ignition cycles that the diagnostic runs and does not fail.

 

 

 

• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

 

 

 

• A history DTC clears after 40?consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

 

 

 

• Clear the MIL and the DTC with a scan tool.

 

Test Description

 

The number below refers to the step number on the diagnostic table.

5 This step tests for the proper operation of the circuit in the high voltage range.

 

Step

 

 

 

Action

 

 

 

Value(s)

 

 

 

Yes

 

 

 

No

 

 

 

Schematic Reference: Engine Controls Schematics

 

Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views

 

 

1

 

 

Did you perform the Diagnostic System Check – Vehicle?

 

 

—

 

 

Go to Step?2

 

 

Go to Diagnostic System Check - Vehicle

 

 

2

 

 

 

 

1. Idle the engine for 1?minute.

 

 

2. Monitor the diagnostic trouble code (DTC) information with a scan tool.

 

Did DTC?P0641 or P0651 fail this ignition?

 

 

—

 

 

Go to Diagnostic Trouble Code (DTC) List - Vehicle

 

 

Go to Step?3

 

 

3

 

 

Observe the fuel tank pressure sensor parameter with the scan tool.

 

Does the scan tool indicate that fuel tank pressure sensor parameter is less than the specified value?

 

 

0.1?V

 

 

Go to Step?5

 

 

Go to Step?4

 

 

4

 

 

 

 

1. Observe the Freeze Frame/Failure Records for this DTC.

 

 

2. Turn OFF the ignition for 30?seconds.

 

 

3. Turn ON the ignition, with the engine OFF.

 

 

4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

 

Did the DTC fail this ignition?

 

 

—

 

 

Go to Step?5

 

 

Go to Testing for Intermittent Conditions and Poor Connections

 

 

<a href="http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=1398849&cellId=30498&pubObjSyskey=2810312&from=sm&pubCellSyskey=347017&deliveryEffectiveDate=Jun+1%2C+2012#td05">5

 

 

 

 

1. Turn OFF the ignition.

 

 

 

2. Raise and support the vehicle. Refer to

Lifting and Jacking the Vehicle .

 

 

 

3. Disconnect the fuel tank wiring harness at the fuel tank harness connector.

 

 

 

4. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the fuel tank pressure (FTP) sensor and the signal circuit of the FTP sensor.

 

 

 

5. Turn ON the ignition, with the engine OFF.

 

 

 

6. Observe the fuel tank pressure sensor voltage with a scan tool.

 

 

Is the fuel tank pressure sensor parameter greater than the specified value?

 

 

4.8?V

 

 

Go to Step?8

 

 

Go to Step?6

 

 

6

 

 

Test the 5-volt reference circuit of the FTP sensor for an open between the fuel tank harness connector and the control module. Refer to Circuit Testing and Wiring Repairs .

 

Did you find and correct the condition?

 

 

—

 

 

Go to Step?12

 

 

Go to Step?7

 

 

7

 

 

Test the signal circuit of the FTP sensor for a short to ground, or an open between the fuel tank harness connector and the control module. Refer to Circuit Testing and Wiring Repairs .

 

Did you find and correct the condition?

 

 

—

 

 

Go to Step?12

 

 

Go to Step?9

 

 

8

 

 

 

 

1. Remove the fuel tank. Refer to

Fuel Tank Replacement .

 

 

 

2. Inspect the fuel tank wiring harness for the following:

 

 

 

• Damaged wiring

 

 

 

• Poor connections

 

 

 

• Broken wires inside the insulation—Refer to

Circuit Testing and Wiring Repairs .

 

 

Did you find and correct the condition?

 

 

—

 

 

Go to Step?12

 

 

Go to Step?10

 

 

9

 

 

Inspect for poor connections at the harness connector of the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

 

Did you find and correct the condition?

 

 

—

 

 

Go to Step?12

 

 

Go to Step?11

 

 

10

 

 

Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement .

 

Did you complete the replacement?

 

 

—

 

 

Go to Step?12

 

 

—

 

 

11

 

 

Replace the powertrain control module (PCM). Refer to Control Module References for replacement, setup, and programming.

 

Did you complete the replacement?

 

 

—

 

 

Go to Step?12

 

 

—

 

 

12

 

 

 

 

1. Observe the Freeze Frame/Failure Records for this DTC.

 

 

 

2. Turn OFF the ignition for 30?seconds.

 

 

 

3. Turn ON the ignition, with the engine OFF.

 

 

 

4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

 

 

Did the DTC fail this ignition?

 

 

—

 

 

Go to Step?2

 

 

Go to Step?13

 

 

13

 

 

Observe the Capture Info with a scan tool.

 

Have any other DTCs not been diagnosed?

 

 

—

 

 

Go to Diagnostic Trouble Code (DTC) List - Vehicle

 

 

System OK

[gmtech4]

snakes code came out much better lol

[dlstewart01]

Thanks so much for your help. I can see where this may not be easy. I don't want to throw parts at it or spend money I don't have to.

 

I will get back on it tomorrow. I may have to get the dealer involved. I can change out the semsor if I knew that was it. I still believe the non operating fuel gage is also part of this problem. I will change out the cluster tomorrow and rule that out. Thats an easy one.

 

Thanks again.

[txab]

Good luck, Don.

[dlstewart01]

Well eliminated the cluster. I had my orginal cluster that I took out when I bought the truck and put a cluster with a trans temp gage in. This cluster only has a few miles and I know it to be good. Put it in and fuel gage does not work and low fuel message.

 

Now I also have code P0463 fuel level sensor circuit high imput. I guess thats causing the fuel gage to not work.

 

I was hoping that some one had had this problem or a dealership person had seen this before.

 

So it looks like I need a fuel tank pressure sensor and a fuel level sender. heck might as well get a new fuel pump. The pump has to come out to replace the sending unit.

 

Oh yeah, the trucks runs perfect.