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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1999 🢒 Eldorado 🢒 Suspension 🢒 Road Sensing Suspension (RSS) 🢒 DTC C1744 Lift/Dive Signal Discrete Fault

Object Number: 258338 Size: SF

Circuit Description

The CVRSS control module receives a lift/dive signal from the Powertrain Control Module (PCM). Under normal conditions, this signal is 5 volts. The PCM grounds this circuit when the vehicle is accelerating rapidly (LIFT) or braking hard (DIVE). When the lift/dive signal goes low (approximately 0 volts), the CVRSS control module commands all four CVRSS dampers to a FIRM condition.

Conditions for Setting the DTC

The DTC is set when the CVRSS control module does not sense the low-to-high transition on the lift/dive line within 31 seconds after the ignition is turned ON.

The DTC turns HISTORY when the CVRSS control module senses the low-to high transition on the lift/dive signal from the PCM during a valid test period.

Action Taken When the DTC Sets
    • The CVRSS lift/dive function will be disabled.
    • The vehicle will pitch more during a braking or wide open throttle condition.
    • The SERVICE RIDE CONTROL message will be displayed.

Conditions for Clearing the MIL/DTC
    • Use the scan tool.
    • Use the On-Board diagnostic CLEAR RSS CODES feature.

Diagnostic Aids

As part of the vehicle diagnostic system, the PCM toggles the lift/dive line within 31 seconds after the ignition is turned ON. This allows the CVRSS module to determine if the line is faulted or not. A retry is attempted every four minutes until successful.

An intermittent short circuit to ground or open circuit condition in CKT 1490 may cause a random firm/soft ride condition.

Test Description

Important: 

   • Do not backprobe the sensors, actuators, or any sealed connectors.
   • When all the diagnostics and repairs are complete, clear the DTCs and verify the operation.

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step checks to see if the related PCM DTC is set.

    2.

  2. This step checks for proper voltage at the CVRSS module when the signal is not active.

    3.

  3. This step manually activates the lift/dive signal (circuit should be at 0 volts).

    4.

  4. This step saves system information and checks for an open circuit condition in CKT 1490.

    5.

  5. This step saves system information and checks for short circuit to ground conditions in CKT 1490.

    6.

  6. This step checks for a short to battery (voltage) condition in CKT 1490.

Step

Action

Value(s)

Yes

No

1

Was the CVRSS System Check performed?

--

Go to Step 2

Go to Road Sensing Suspension Diagnostic System Check

2

Is DTC P1652 set?

--

Go to DTC P1652 Powertrain Induced Chassis Pitch Output Circuit in Engine Controls

Go to Step 3

3

  1. Turn the ignition ON.
  2. Backprobe pin C5 of CVRSS module connector C1 and measure the voltage to ground.

Is the measurement within the specified values?

4-6 V

Go to Step 4

Go to Step 11

4

  1. Connect the scan tool.
  2. Continue to backprobe pin C5 with voltmeter.
  3. Within the scan tool option MISC. TESTS (in the Powertrain section of scan tool), select MORE, then RIDE CONTROL.
  4. Command the Ride Control to FIRM.
  5. Within 5 seconds measure the voltage between pin C5 and ground.

Is the measurement less than the specified value?

1 V

Go to Step 10

Go to Step 5

5

  1. Store the fluid life.
  2. Turn the ignition OFF.
  3. Wait 30 seconds.
  4. Disconnect PCM connector C1.
  5. Check for proper seating of pin 24 at the PCM connector.

Was the terminal seated properly?

--

Go to Step 6

Go to Step 7

6
  1. Disconnect CVRSS connector C1.
  2. Check for an open circuit condition in CKT 1490.

Was an open circuit condition found?

--

Go to Step 8

Go to Step 9

7

Repair the connector.

Is the repair complete?

--

Go to Road Sensing Suspension Diagnostic System Check

--

8
  1. Repair the open circuit condition in CKT 1490.
  2. Install all of the connectors and components that were removed.
  3. Turn the ignition ON with the engine off.
  4. Clear all RSS DTCs. Refer to Clearing DTCs .

Is the repair complete?

--

Go to Road Sensing Suspension Diagnostic System Check

--

9

Replace the PCM.

Is the replacement complete?

--

Go to Road Sensing Suspension Diagnostic System Check

--

10
  1. Turn the ignition OFF.
  2. Replace the CVRSS control module. Refer to Electronic Suspension Control Module Replacement .
  3. Install all the connectors and components that were removed.
  4. Install the scan tool.
  5. Turn the ignition ON with the engine off.

    6. Important: The controller must be calibrated.

  6. Calibrate the CVRSS service controller using the scan tool. Refer to Electronic Suspension Control Module Calibration .

Is the CVRSS control module calibrated?

--

Go to Road Sensing Suspension Diagnostic System Check

--

11

  1. Store the fluid life.
  2. Turn the ignition OFF.
  3. Wait 30 seconds.
  4. Disconnect PCM connector C1.
  5. Disconnect CVRSS connector C1.
  6. Check for proper seating of pin C5 at CVRSS connector C1.
  7. Check for a continuity to ground condition in CKT 1490.

Was a short circuit to ground condition found?

--

Go to Step 12

Go to Step 13

12
  1. Repair the short circuit to ground condition in CKT 1490.
  2. Install all of the connectors and components that were removed.
  3. Turn the ignition ON with the engine off.
  4. Clear the CVRSS and PCM DTCs. Refer to Clearing DTCs .

Is the repair complete?

--

Go to Road Sensing Suspension Diagnostic System Check

--

13

  1. Turn the ignition ON with the engine off.
  2. Measure the voltage on CKT 1490.

Is the measurement less than the specified value?

6 V

Go to Step 10

Go to Step 14

14
  1. Repair the short to battery condition in CKT 1490.
  2. Install all of the connectors and components that were removed.
  3. Turn the ignition ON.
  4. Clear the CVRSS and PCM DTCs. Refer to Clearing DTCs .

Is the repair complete?

--

Go to Road Sensing Suspension Diagnostic System Check

--