Error Code C0712 2016 GMC Denali XL Suspension very rough

[NashRed]

Hello. I have been combing Suspension threads here for a few days. My car has been riding rough --really rough and we took it to a reputable Suspension company here locally--not a dealership. If you try to bounce the front of the car--it does not move. The rear bounces with about 2 rebounds. I have zero noise with the air bag compressor like I did with my 2011 Denali XL. That being said, this place is saying the car is throwing an internal service code C0712 ( it did not make the dashboard service light come on at all). I can only find very little information on this code, especially this forum. They want 5200 bucks to replace front struts, air ride compressor, and rear shocks. My question is one, what exactly is this error code and most common cause? Two, if this code is related to the Electronic Suspension Control Module would that mean the module is the problem or is it also the front struts separately? We will most likely not keep this car more than a year or 2. I am really curious considering how many threads there are on this magnaride system yet no one talks or mentions this error Code. Thank you in advance for your opinion.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

Take a look at the document below, and see if this is helpful to you. If you have a quality bi-directional scanner (like a Tech 2), you can zero in on the source of the issue, rather than simply replacing everything.

I would look at the 4 level sensors, one at each wheel, as see if there is damage to them, and if the electrical wires are tightly connected. With a quality scanner, I could look at the variable resistance in each of the sensors to see if one of them is failing.

If the sensors function properly, I would then use the quality scanner to check out the operation of the compressor and its relief valve.


GM Service Manual Online
For 1990-2009 cars only
Makes GMC_Truck 2007 Yukon Denali DTC DTC C0712

Diagnostic Instructions​

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors​

DTC C0712 01: Level Control Compressor Relay Circuit Short to Voltage.

DTC C0712 06: Level Control Compressor Relay Circuit Short to Ground or Open.

Circuit/System Description​

The Automatic Level Control (ALC) system uses a compressor relay to switch 12 volts to the compressor motor. The electronic suspension control module (ESCM) receives inputs from the suspension position sensors and air pressure sensor to determine when to raise the rear of the vehicle by grounding the relay coil circuit, and monitoring to ensure it agrees with the command.

Conditions for Running the DTC​

C0712 01​

•	The ignition is ON.

•	The relay is commanded ON.

C0712 06​

•	The ignition is ON.

•	The relay is commanded OFF.

Conditions for Setting the DTC​

C0712 01​

Upon detection of the compressor relay control circuit is shorted to battery.

C0712 06​

Upon detection of the compressor relay control circuit shorted to ground, or open.

Action Taken When the DTC Sets​

C0712 01 06​

•	DTC C0712 is stored in memory.

•	The driver information center (DIC) displays the SERVICE SUSPENSION SYSTEM message after detection for 3 consecutive ignition ON cycles.

•	The ALC system is disabled.

Conditions for Clearing the DTC​

•	A current DTC will clear when the malfunction is no longer present.

•	The history DTC will clear after 100 fault-free ignition cycles.

Reference Information​

Schematic Reference​

Automatic Level Control Schematics

Connector End View Reference​

Automatic Level Control Connector End Views

Description and Operation​

Automatic Level Control Description and Operation

Electrical Information Reference​

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Scan Tool Reference​

•	Scan Tool Data List

•	Scan Tool Data Definitions

•	Scan Tool Output Controls

Circuit/System Verification​

Ignition ON, command the compressor relay ON and OFF with a scan tool. Listen for the compressor running or relay clicks.

Circuit/System Testing​

1. Ignition OFF, disconnect the harness connector at the compressor relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 86 and ground.

3. ⇒	If the test lamp illuminates, test the control circuit for a short to voltage.

4. Verify that a test lamp illuminates between the ignition circuit terminal 85 and ground.

5. ⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test or replace the compressor relay.

6. Verify that a test lamp illuminates between the ignition circuit terminal 30 and ground.

7. ⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test the control circuit at terminal 87 for a short to ground.

8. Disconnect the harness connector at the air compressor.
9. Test for less than 1 ohm of resistance between the air compressor ground circuit terminal G and ground.

10. ⇒	If greater than 1 ohm, test the ground circuit for an open/high resistance.

11. Connect the harness connector at the air compressor.
12. Connect a 40-A used jumper wire between the ignition circuit terminal 30 and the control circuit terminal 87. Verify the air compressor is activated.

13. ⇒	If the air compressor does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the air compressor.

14. Connect a test lamp between the ignition circuit terminal 85 and the control circuit terminal 86.
15. Command the compressor relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

16. ⇒	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ESC module.

    ⇒	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ESC module.

17. If all circuits test normal, test or replace the compressor relay.

Repair Instructions​

•	Air Compressor Replacement

•	Control Module References for ESCM replacement, setup, and programming

Repair Verification​

1. Install any components or connectors that have been removed or replaced during diagnosis.
2. Perform any adjustment, programming or setup procedures that are required when a component or module is removed or replaced.
3. Clear the DTCs.
4. Use the scan tool Diagnostic Counter Reset output control function to bypass the 3 consecutive ignition cycle requirement for setting a DTC. This will ensure that if a DTC was to be reset during the repair verification process, it will be displayed on the scan tool.
5. Turn OFF the ignition for 60 seconds.
6. Turn ON the ignition.
7. If the repair was related to a DTC, duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to the Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedure.

 

[NashRed]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

Take a look at the document below, and see if this is helpful to you. If you have a quality bi-directional scanner (like a Tech 2), you can zero in on the source of the issue, rather than simply replacing everything.

I would look at the 4 level sensors, one at each wheel, as see if there is damage to them, and if the electrical wires are tightly connected. With a quality scanner, I could look at the variable resistance in each of the sensors to see if one of them is failing.

If the sensors function properly, I would then use the quality scanner to check out the operation of the compressor and its relief valve.


GM Service Manual Online
For 1990-2009 cars only
Makes GMC_Truck 2007 Yukon Denali DTC DTC C0712

Diagnostic Instructions​

​

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

​

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

​

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors​

DTC C0712 01: Level Control Compressor Relay Circuit Short to Voltage.

DTC C0712 06: Level Control Compressor Relay Circuit Short to Ground or Open.

Circuit/System Description​

The Automatic Level Control (ALC) system uses a compressor relay to switch 12 volts to the compressor motor. The electronic suspension control module (ESCM) receives inputs from the suspension position sensors and air pressure sensor to determine when to raise the rear of the vehicle by grounding the relay coil circuit, and monitoring to ensure it agrees with the command.

Conditions for Running the DTC​

C0712 01​

​

•	The ignition is ON.

​

•	The relay is commanded ON.

C0712 06​

​

•	The ignition is ON.

​

•	The relay is commanded OFF.

Conditions for Setting the DTC​

C0712 01​

Upon detection of the compressor relay control circuit is shorted to battery.

C0712 06​

Upon detection of the compressor relay control circuit shorted to ground, or open.

Action Taken When the DTC Sets​

C0712 01 06​

​

•	DTC C0712 is stored in memory.

​

•	The driver information center (DIC) displays the SERVICE SUSPENSION SYSTEM message after detection for 3 consecutive ignition ON cycles.

​

•	The ALC system is disabled.

Conditions for Clearing the DTC​

​

•	A current DTC will clear when the malfunction is no longer present.

​

•	The history DTC will clear after 100 fault-free ignition cycles.

Reference Information​

Schematic Reference​

Automatic Level Control Schematics

Connector End View Reference​

Automatic Level Control Connector End Views

Description and Operation​

Automatic Level Control Description and Operation

Electrical Information Reference​

​

•	Circuit Testing

​

•	Connector Repairs

​

•	Testing for Intermittent Conditions and Poor Connections

​

•	Wiring Repairs

Scan Tool Reference​

​

•	Scan Tool Data List

​

•	Scan Tool Data Definitions

​

•	Scan Tool Output Controls

Circuit/System Verification​

Ignition ON, command the compressor relay ON and OFF with a scan tool. Listen for the compressor running or relay clicks.

Circuit/System Testing​

1. Ignition OFF, disconnect the harness connector at the compressor relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 86 and ground.
3. ​

   ⇒	If the test lamp illuminates, test the control circuit for a short to voltage.

   
   
4. Verify that a test lamp illuminates between the ignition circuit terminal 85 and ground.
5. ​

   ⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test or replace the compressor relay.

   
   
6. Verify that a test lamp illuminates between the ignition circuit terminal 30 and ground.
7. ​

   ⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test the control circuit at terminal 87 for a short to ground.

   
   
8. Disconnect the harness connector at the air compressor.
9. Test for less than 1 ohm of resistance between the air compressor ground circuit terminal G and ground.
10. ​

    ⇒	If greater than 1 ohm, test the ground circuit for an open/high resistance.

    
    
11. Connect the harness connector at the air compressor.
12. Connect a 40-A used jumper wire between the ignition circuit terminal 30 and the control circuit terminal 87. Verify the air compressor is activated.
13. ​

    ⇒	If the air compressor does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the air compressor.

    
    
14. Connect a test lamp between the ignition circuit terminal 85 and the control circuit terminal 86.
15. Command the compressor relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
16. ​

    ⇒	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ESC module.

    
    
    ​

    ⇒	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ESC module.

    
    
17. If all circuits test normal, test or replace the compressor relay.

Repair Instructions​

​

•	Air Compressor Replacement

​

•	Control Module References for ESCM replacement, setup, and programming

Repair Verification​

1. Install any components or connectors that have been removed or replaced during diagnosis.
2. Perform any adjustment, programming or setup procedures that are required when a component or module is removed or replaced.
3. Clear the DTCs.
4. Use the scan tool Diagnostic Counter Reset output control function to bypass the 3 consecutive ignition cycle requirement for setting a DTC. This will ensure that if a DTC was to be reset during the repair verification process, it will be displayed on the scan tool.
5. Turn OFF the ignition for 60 seconds.
6. Turn ON the ignition.
7. If the repair was related to a DTC, duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to the Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedure.

Thank you for your response. I do not know if the scanner detected C0712 - 1 or 6. I will upload a pic when I find one. This is a 2016. The manual was for older models... Or did I miss the right one?

 

[Joseph Garcia]

Thank you for your response. I do not know if the scanner detected C0712 - 1 or 6. I will upload a pic when I find one. This is a 2016. The manual was for older models... Or did I miss the right one?

The level sensors and the air compressor are the same on the 2016 model truck. Only the actual shocks are different only in how they change stiffness - 2016 - Z95 Magneride suspension; 2007 - Z55 Electronic suspension