Hi guys,
It's been almost 1 year and I still did not get my car running right. I have issues after issues that sometimes make me regret owning the car. Well here is the current issue.
I have the F45 option and the Bilstein sport shocks. In order to make this work, I installed a set of simulators. Everything has been fine until about 1 week ago. I moved the F45 selector from Performance to sport by accident and the car max speed was 80 mph. So I pulled the codes and it said:
RTD 1786 HC
RTD 1787 HC
I replaced all the 4 sims and looked into the fuse box under the hood. The RTD fuse (fuse number 7 was burnt, it's a 10A fuse). I replaced it. Everything was fine. I drove the car for half a mile. I got this message:
"Service ride control" "maximum speed 80mph" and so on. I parked the car, looked in the fuse box, the fuse was burnt again, I changed it and about 2 minutes later the same happened. And again and again. I changed the fuse 4 times and the issue is still there.

Please help me enjoy my car. After one year of issues I still can't enjoy my car. I installed a forged 408 in septemeber and only put 500 miles on the car. I always have issues. Guys please help me.

Right nw, the car is in the garage for a belt swap. I will get it back this weekend so I will try wathever you guys advise me; But in the mean time, please give me all the advice possible. I really need YOU!!


Thank you so much in advance, I hope that once again, you guys will be able to get me back on the road so that I can enjoy my Vette

With my kindest regards,
David

 

David

Just DELETE that damn F-45 RPO code from the Body Control Module (BCM) and be DONE WITH F-45 crap!!!!!!!.

You will need to find some one with a GM Tech II. That is the only device that can interface and re-program the BCM. The procedure is straight forward. Anyone who has a TECH II should be able to remove that RPO Code from your BCM.

Once the RPO Code is removed, you can remove the module from the rear hatch well, the wheel position sensors, the switch on the console etc....

In the mean time, when I get home tonight, I will post some schematics for you.

Bill C

 

Bill,
What can I say? You rock, always there to help. Thank you so much. I will wait for your schematics and I will take an appointment at the dealership and I will tell them to remove that crap. I am telling you, this F45 suspension is a nightmare.

Could you give me the exact instructions on what to do with the Tech II. I am 100% sure that they won't want to do it unless I tell them exactly what to do Welcome to France

 

These are instructions for a different RPO to be turned ON/OFF ... but note the F45 option in the last screen of the description of how to turn on Twilight Sentinal.

http://www.stopforce.com/RPO.html

WARNING - be certain you have already disconnected the computer that controls F45 before turning off this option. If you turn off the option with the computer still installed ... the next time you turn on the car the option will turn back ON automatically, requiring another visit to the dealer.

 

YES IT SURE WILL!!! Thanks for the back up and posting up the stopforce link!! I was at work and didnt have access to my computer.

BC

 

Thanks a lot guys!! I will keep you posted when I get my car back with the new belt. I will head straight to the dealer and get that deleted

Thanks again guys!

 

Oh, one last question. The tech II operation won't affect my tune right? Or do I have to plug HP tuners back in the car and load my tune again?

Thanks again!

 

Your "tune" is loaded in the PCM. The RPO list that is being changed is in the BCM. Unless the guy with the Tech2 goes berserk .... no effect to your tune ....

Just be sure the F45 control computer is unplugged (removed) before the Tech2 procedure is done.

 

And don't kill yourself after you get it fixed....

You should ALWAYS have a backup of your tune.

 

David

Heres the schematicc for what you need to fix the two DTCs listed:



Here is the repair procedure for DTC 1787:

Circuit Description
Solenoid supply voltage is applied to the ESC module through the RTD relay circuit. The ESC module controls the RTD relay by grounding CKT 1944. This closes the relay contacts providing each shock absorber solenoid with supply voltage through the ESC module's internal solenoid supply circuitry. Each individual solenoid drive then controls the operation of the corresponding shock absorber. The ESC module monitors the RTD relay control/solenoid supply circuits for any malfunction conditions.

Conditions for Setting the DTC
The ESC module detects low voltage (an open or a short to ground) on the RTD relay control CKT 1944.
Detection for this DTC can only be accomplished during the OFF (relay not applied) state.
Action Taken When the DTC Sets
Stores a DTC C1787 in the ESC memory.
Commands 0% PWM duty cycle in order to disable all four solenoids.
Sends a message to the IPC to display the SERVICE RIDE CONTROL and the SHOCKS INOPERATIVE messages.
Sends a message to the PCM to limit the speed. The PCM then sends a massage to the IPC to display the MAXIMUM SPEED 129 km/h (80 mph) message.
Conditions for Clearing the DTC
The ignition must be cycled before this DTC can change from current to history even if the malfunction is no longer present.
The ESC module no longer detects low voltage (an open or a short to ground) on the RTD relay control CKT 1944 with the relay OFF.
A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
The IPC clearing DTCs feature.
Using a scan tool.
Diagnostic Aids
The following conditions may cause an intermittent malfunction:
An open or a short to ground on the RTD relay control CKT 1944.
An open RTD relay coil or high resistance condition.
An open RTD relay fuse #7.
A short to ground on any shock absorber solenoid supply circuit.
The RTD relay may be installed in the underhood electrical center in two directions and still function properly. Refer to Power Distribution Schematics in Wiring Systems for electrical center identification.
The RTD relay provides supply voltage to all four shock absorber solenoids. Therefore, multiple shock absorber solenoid open or short to ground DTCs may also be stored along with a DTC C1786. Diagnose a DTC C1787 first before attempting to diagnose multiple shock absorber solenoid DTCs.
Test Description
The numbers below refer to the step numbers on the diagnostic table:

This step checks the underhood electrical center supply voltage.

This step checks for a short to ground on the RTD relay control CKT 1944.

This step measures the resistance of the RTD relay coil.

This step checks for an open on the RTD relay control CKT 1944.

This step checks for an intermittent malfunction and requests a thorough inspection of the related RTD relay circuit wiring and connectors.

DTC C1787 -- RTD Relay Circuit Open or Shorted to Ground Step
Action
Value(s)
Yes
No

1
Was the RTD Diagnostic System Check performed?
--
Go to Step 2
Go to RTD Diagnostic System Check

2
Turn OFF the ignition switch.
Disconnect the RTD relay.
Turn ON the ignition switch.
At the underhood electrical center, measure the voltage on the RTD relay Batt circuit terminal. Refer to Power Distribution Schematics in Wiring Systems for electrical center identification.
Is the voltage indicated over the specified value?
10.0 V
Go to Step 3
Go to Step 9

3
Turn OFF the ignition switch.
Disconnect the ESC module connector C2.
At the underhood electrical center, check for continuity between CKT 1944 and ground. Refer to Power Distribution Schematics in Wiring Systems for electrical center identification.
Is there continuity?
--
Go to Step 7
Go to Step 4

4
Measure the resistance of the RTD relay coil between terminals 1 and 2 (or 85 and 86).

Is the resistance reading within the specified value?
75-105 ohms
Go to Step 5
Go to Step 10

5
Turn OFF the ignition switch.
Reconnect the RTD relay.
At the harness side of the ESC module connector C2, measure the voltage at terminal C13.
Was the voltage indicated over the specified value?
10.0 V
Go to Step 6
Go to Step 8

6
Check the RTD relay circuit for an intermittent malfunction. Refer to Diagnostic Aids.

Was an intermittent malfunction found and repaired?
--
Go to Step 12
Go to Step 11

7
Locate and repair the short to ground in the underhood electrical center or CKT 1944.

Is the circuit repair complete?
--
Go to Step 12
--

8
Locate and repair the open in CKT 1040.

Is the circuit repair complete?
--
Go to Step 12
--

9
Locate and repair the open in the underhood electrical center, the RTD open fuse, or the power feed to the underhood electrical center.

Is the circuit repair complete?
--
Go to Step 12
--

10
Replace the RTD relay.

Is the repair complete?
--
Go to Step 12
--

11
Replace the ESC module. Refer to Electronic Suspension Control Module Replacement .

Is the repair complete?
--
Go to Step 12
--

12
Turn OFF the ignition switch.
Connect or install any connectors or components that were disconnected or removed.
Turn ON the ignition switch.
Using a scan tool, select clear DTCs.
Is the repair complete?
--
Go to RTD Diagnostic System Check
--


Repair procedure for 1787

DTC C1786 RTD Relay Malfunction




Circuit Description
Solenoid supply voltage is applied to the ESC module through the RTD relay circuit. The ESC module controls the RTD relay by grounding CKT 1944. This closes the relay contacts providing each shock absorber solenoid with supply voltage through the ESC module's internal solenoid supply circuitry. Each individual solenoid drive then controls the operation of the corresponding shock absorber. The ESC module monitors the RTD relay control/solenoid supply circuits for any malfunction conditions.

Conditions for Setting the DTC
The ESC module detects low voltage (an open or a short to ground) on the RTD relay solenoid supply CKT 1040.
There is a loss of voltage on all four shock absorber supply circuits.
Detection for this DTC can only be accomplished during the ON (relay applied) state.
Action Taken When the DTC Sets
Stores a DTC C1786 in the ESC memory.
Commands 0% PWM duty cycle in order to disable all four solenoids.
Sends a message to the IPC to display the SERVICE RIDE CONTROL and SHOCKS INOPERATIVE messages.
Sends a message to the PCM to limit the speed. The PCM then sends a message to the IPC to display the MAXIMUM SPEED 129 km/h (80 mph) message.
Conditions for Clearing the DTC
The ESC module no longer detects low voltage (an open or a short to ground) on the RTD relay solenoid supply CKT 1040.
No shock absorber short to ground DTCs are present.
A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
The IPC clearing DTCs feature
Using a scan tool.
Diagnostic Aids
The following conditions may cause an intermittent malfunction:
An open or a short to ground on the RTD relay solenoid supply CKT 1040.
An open RTD relay contact(s).
An open or removed RTD relay fuse #7.
A short to ground on any shock absorber solenoid supply circuits.
The RTD relay provides supply voltage to all four shock absorber solenoids. Therefore, multiple shock absorber solenoid open or short to ground DTCs may also be stored along with a DTC C1786. Diagnose a DTC C1786 first before attempting to diagnose multiple shock absorber solenoid DTCs.
The RTD relay may be installed in the underhood electrical center in two directions and still function properly. Refer to Power Distribution Schematics in Wiring Systems for electrical center identification.
If the conditions for a DTC C1786 are current, the ESC module will command 0% PWM duty cycle in order to disable all four solenoids. The vehicle will experience a soft ride condition.
Test Description
The numbers below refer to the step numbers on the diagnostic table:

This step checks if DTCs C1787 or C1788 are stored in the ESC module. These DTCs may cause a DTC C1786 to store.

This step checks if the RTD relay fuse is open. A DTC C1786 will set if the RTD fuse is open or removed.

This step checks if supply voltage is available to the ESC module at terminal D1.

This step checks the battery circuit to the RTD relay.

This step checks if a short to ground is present in the CKT 1040 or the RTD relay.

This step checks for a short to ground on all solenoid supply circuits.

DTC C1786 -- RTD Relay Malfunction Step
Action
Value(s)
Yes
No

1
Was the RTD Diagnostic System Check performed?
--
Go to Step 2
Go to RTD Diagnostic System Check

2
Using a scan tool, check if DTCs C1787 or C1788 are stored.

Are any of the indicated DTCs stored?
--
Go to Applicable DTC Table
Go to Step 3

3
Check the RTD Relay Fuse #7.

Is the RTD relay fuse open?
--
Go to Step 6
Go to Step 4

4
Turn ON the ignition switch.
At the harness side of the ESC module connector C2, backprobe terminal D1 while measuring the voltage.
Was the voltage indicated over the specified value?
10.0 V
Go to Step 10
Go to Step 5

5
Turn OFF the ignition switch.
Disconnect the RTD relay.
At the underhood electrical center, measure the voltage on the RTD relay Batt circuit terminal. Refer to Power Distribution Schematics in Wiring Systems for electrical center identification.
Was the voltage indicated over the specified value?
10.0 V
Go to Step 8
Go to Step 9

6
Turn OFF the ignition switch.
Disconnect the ESC module connector C2.
At the harness side of the ESC module connector C2, check for continuity between terminal D1 and ground.
Is there continuity?
--
Go to Step 8
Go to Step 7

7
Check all four shock absorber solenoid supply circuits for a short to ground (CKTs 1114, 1116, 1107 and 1118).

Was a circuit problem found and repaired?
--
Go to Step 13
Go to Step 12

8
Check for an open or short to ground in CKT 1040.

Was a problem found and repaired?
--
Go to Step 13
Go to Step 11

9
Locate and repair the open in the underhood electrical center or the power feed to the electrical center.

Is the circuit repair complete?
--
Go to Step 13
--

10
Check the RTD relay solenoid supply circuit for the following intermittent malfunctions:

Short to ground in CKT 1040.
Short to ground on any shock absorber solenoid supply circuit.
Was an intermittent malfunction found and repaired?
--
Go to Step 13
System OK

11
Replace the RTD relay.

Is the repair complete?
--
Go to Step 13
--

12
Replace the ESC module. Refer to Electronic Suspension Control Module Replacement .

Is the repair complete?
--
Go to Step 13
--

13
Turn OFF the ignition switch.
Connect or install any connectors or components that were disconnected or removed.
Turn ON the ignition switch.
Using a scan tool, select clear DTCs.
Is the repair complete?
--
Go to RTD Diagnostic System Check
--

 

Thank you so much guys!!! I will defninitely disconnect the RTD before going to the dealer

Bill!!! I don't know what to say You're amazing. I really hope we can meet again soon. I should come to the USA during the winter with my GF. If I come, I will certainly visit you