LBZ: Electrical gremlins... Help p0652

[TeaBagger2006]

So the ole lbz finally left me stranded in 11 years. It's an electrical problem 100%.she starts knocking really bad, like when you unplug the regulator on the cp3. Throttle response is extremely sluggish. My fuel, coolant, and oil pressure gauges go crazy and set off all the corresponding warnings and codes. I get p0652, which is a 5v code, along with glow plug codes. I cleaned the front engine block ground which is associated with all of those items. The ground was saturated in oil and grime, the smaller ground looked like it's had a rough life.

....anyways I cleaned them up and reinstalled them and truck fired up like normal. After a couple minutes it started running really rough again and the gauges went crazy again. So I removed the grounds again for an even more thorough cleaning. I reinstalled them and the truck fired up normally. After about 10 minutes it started doing the same crap again.

Any ideas where to go next? I'm thinking about replacing the ends on the grounds...

 

[jlawles2]

Sounds like one of them may be broke.

Don't forget to check the ground on the back of the block to the cab.

I think there is also a ground from the cab to the frame on the driver side front cab mount.

 

[CarolinaHD]

Check the main wiring harness right above the drivers side shock to see if its chaffing. There should be another ground on the front driver cab mount, check it too

 

[KyleC4]

Perform a voltage drop test on the grounds. But because P0652 is a 5v ref circuit, any of the components on that circuit can cause this code to set. The APP sensor 2, A/C pressure sensor, Oil pressure sensor, and fuel rail pressure sensor can have a circuit with a chafed wire in it causing concern. Or even the sensor itself could be faulty.

 

[juddski88]

Check to make sure the 5v wire at the FPR jumper harness connections is not broken or loosened. I chased something similar for a couple months on an lbz

 

[Ron Nielson]

Maybe some help in here for you:


P0652
Circuit/System Description

The engine control module (ECM) supplies 5 volts to components through 5-volt reference circuits. These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together in three reference groups inside the ECM. Therefore, a circuit condition on one sensor 5-volt reference circuit may affect multiple components. The ECM monitors voltage on the 5-volt reference circuits.

Conditions for Running the DTC

The ignition is ON.
The diagnostics run continuously.

Conditions for Setting the DTC

P0652

The ECM detects the 5-volt reference 2 circuit voltage is less than 4.7 volts.
The above condition is present for 2 seconds.

P0653

The ECM detects the 5-volt reference 2 circuit voltage is more than 5.2 volts.
The above condition is present for 2 seconds.

Action Taken When the DTC Sets

The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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.

Circuit/System Verification

The engine starts and runs.
Observe the 5-Volt Reference 2 Circuit Status parameter with a scan tool. The parameter should display OK.
Engine running, observe the DTC information with a scan tool. DTCs P0652 or P0653 should not set.
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 data.

Circuit/System Testing

Turn OFF the ignition for 30 seconds or until the ECM powers down.
Disconnect the accelerator pedal position (APP) sensor.
Turn ON the ignition, with engine OFF and measure the voltage from the 5-volt reference circuit of the APP sensor 2 to a good ground with a DMM.

If the voltage measures 4.7-5.2 volts, replace the APP sensor.

With the DMM still connected to the 5-volt reference circuit, disconnect all other components connected to the 5-volt reference 2, one at a time.

If voltage changes when one of the above components is disconnected, replace the component.

Test the 5-volt reference 2 circuits for a short to ground or a short to voltage.

If no problem was found in the 5-volt reference 2 circuit, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. See: Verification Tests

Accelerator Pedal Position Sensor Replacement
Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (Non-HP2)
Engine Oil Level Sensor and/or Switch Replacement
Exhaust Pressure Differential Sensor Replacement (Pickup) Exhaust Pressure Differential Sensor Replacement (Cab/Chassis)
Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement[/B]
Circuit/System Description

The engine control module (ECM) supplies 5 volts to components through 5-volt reference circuits. These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together in three reference groups inside the ECM. Therefore, a circuit condition on one sensor 5-volt reference circuit may affect multiple components. The ECM monitors voltage on the 5-volt reference circuits.

Conditions for Running the DTC

The ignition is ON.
The diagnostics run continuously.

Conditions for Setting the DTC

P0652

The ECM detects the 5-volt reference 2 circuit voltage is less than 4.7 volts.
The above condition is present for 2 seconds.

P0653

The ECM detects the 5-volt reference 2 circuit voltage is more than 5.2 volts.
The above condition is present for 2 seconds.

Action Taken When the DTC Sets

The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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.

Circuit/System Verification

The engine starts and runs.
Observe the 5-Volt Reference 2 Circuit Status parameter with a scan tool. The parameter should display OK.
Engine running, observe the DTC information with a scan tool. DTCs P0652 or P0653 should not set.
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 data.

Circuit/System Testing

Turn OFF the ignition for 30 seconds or until the ECM powers down.
Disconnect the accelerator pedal position (APP) sensor.
Turn ON the ignition, with engine OFF and measure the voltage from the 5-volt reference circuit of the APP sensor 2 to a good ground with a DMM.

If the voltage measures 4.7-5.2 volts, replace the APP sensor.

With the DMM still connected to the 5-volt reference circuit, disconnect all other components connected to the 5-volt reference 2, one at a time.

If voltage changes when one of the above components is disconnected, replace the component.

Test the 5-volt reference 2 circuits for a short to ground or a short to voltage.

If no problem was found in the 5-volt reference 2 circuit, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. See: Verification Tests

Accelerator Pedal Position Sensor Replacement
Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (Non-HP2)
Engine Oil Level Sensor and/or Switch Replacement
Exhaust Pressure Differential Sensor Replacement (Pickup) Exhaust Pressure Differential Sensor Replacement (Cab/Chassis)
Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement

 

[Ron Nielson]

Maybe some help in here for you:


P0652
Circuit/System Description

The engine control module (ECM) supplies 5 volts to components through 5-volt reference circuits. These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together in three reference groups inside the ECM. Therefore, a circuit condition on one sensor 5-volt reference circuit may affect multiple components. The ECM monitors voltage on the 5-volt reference circuits.

Conditions for Running the DTC

The ignition is ON.
The diagnostics run continuously.

Conditions for Setting the DTC

P0652

The ECM detects the 5-volt reference 2 circuit voltage is less than 4.7 volts.
The above condition is present for 2 seconds.

P0653

The ECM detects the 5-volt reference 2 circuit voltage is more than 5.2 volts.
The above condition is present for 2 seconds.

Action Taken When the DTC Sets

The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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.

Circuit/System Verification

The engine starts and runs.
Observe the 5-Volt Reference 2 Circuit Status parameter with a scan tool. The parameter should display OK.
Engine running, observe the DTC information with a scan tool. DTCs P0652 or P0653 should not set.
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 data.

Circuit/System Testing

Turn OFF the ignition for 30 seconds or until the ECM powers down.
Disconnect the accelerator pedal position (APP) sensor.
Turn ON the ignition, with engine OFF and measure the voltage from the 5-volt reference circuit of the APP sensor 2 to a good ground with a DMM.

If the voltage measures 4.7-5.2 volts, replace the APP sensor.

With the DMM still connected to the 5-volt reference circuit, disconnect all other components connected to the 5-volt reference 2, one at a time.

If voltage changes when one of the above components is disconnected, replace the component.

Test the 5-volt reference 2 circuits for a short to ground or a short to voltage.

If no problem was found in the 5-volt reference 2 circuit, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. See: Verification Tests

Accelerator Pedal Position Sensor Replacement
Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (Non-HP2)
Engine Oil Level Sensor and/or Switch Replacement
Exhaust Pressure Differential Sensor Replacement (Pickup) Exhaust Pressure Differential Sensor Replacement (Cab/Chassis)
Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement

 

[TeaBagger2006]

This gremlin is giving me hell. The truck is running fine for now but the problem is random which is extremely frustrating. I replaced the FPR with a new one from LDS yesterday and she runs fine. Now that I think about it the FPR has nothing to do with the 5v system. She's running real fine at the moment,put 50 miles with no issues. No CEL for any of those sensors.... I cleaned the grounds very well..

It's giving me hell boys

 

[jlawles2]

Nephew had a sales guy in his shop with a dmax that was displaying symptoms of every system failing. turns out that something in the bail connector wiring harness on top of the engine was loose or broke. Gauges all acted funny, would not turn over, etc, almost sounded like a bad BCM. It was a 2016 truck with over 100k on it.