DTC P1652 Powertrain Induced Chassis Pitch Output Circuit. Cadillac Concours 1997

For 1990-2009 cars
Engine Controls Components
EBTCM/ Generator/ A/C Relay/ RSS
OBD II Symbol Description Notice
ESD Notice
ESD Notice
ESD Notice

### Circuit Description

The PCM contains chips called Output Driver Modules that provide 7 switchable ground outputs for operating solenoids, relays, telltales, and other devices. Each of these ground outputs has an internal fault line that feeds back to the PCM's microprocessor. When the output is OFF, the output driver should receive the 5 volts fed to the solenoid, relay, etc. When the output is ON, it should receive 0 volt since it is grounding the output. If it receives 0 volt when the output is OFF or 5 volts when the output is ON, it sets the fault line low. DTC P1652 is used to monitor the fault line of the Lift/Dive output to the RSS module. The RSS module sends a 5 volt signal to the PCM connector C1 terminal 24. The PCM then grounds this circuit when the vehicle is accelerating rapidly (LIFT) or braking hard (DIVE). The RSS module will then command the suspension to FIRM to increase controllability of the vehicle during these conditions.

### Conditions for Setting the DTC

#### Test Conditions

• | DTC P1650 not set.

• | Engine running for at least 10 seconds.

#### Failure Condition

Fault line is low for 2 seconds.

### Action Taken When the DTC Sets

• | The Malfunction Indicator Lamp (MIL) will not illuminate.

• | No message will be displayed.

### Conditions for Clearing the DTC

• | A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.

• | A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.

• | Use a scan tool to clear DTCs.

• | Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation.

### Diagnostic Aids

Use the Failure Rec. to aid in diagnosing an intermittent fault. Use the data captured when the DTC set to determine if an open or shorted condition caused the DTC to set.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to A Powertrain On Board Diagnostic (OBD) System Check

2

1. Connect the scan tool.
2. Turn the key ON.
3. Check the PCM Ride Control Output Signal display.

Does the display indicate OK?

--

Go to Step 3

Go to Step 5

3

1. Start and idle the engine.
2. Using a scan tool command the ride control to Firm.

Does the PCM Ride Control Output Signal display indicate OK?

--

Fault not present. Refer to Diagnostic Aids

Go to Step 4

4

1. Turn the key to LOCK.
2. Disconnect the RSS module connector.
3. Turn the key ON.
4. Using DMM J 39200 measure the voltage to ground on the Lift/Dive circuit at the RSS module connector terminal (harness side).

Is the voltage the same or more than the value specified?

0.5 volts

Go to Step 8

Go to Step 12

5

1. Record the fluid life indexes, turn the key to LOCK and wait 30 seconds.
2. Disconnect PCM connector C1.
3. Turn the key ON.
4. Using DMM J 39200 measure the voltage to ground at PCM connector C1 terminal 24.

Is the voltage the same or more than the value specified?

4.5 volts

Go to Step 12

Go to Step 6

6

1. Turn the key to LOCK.
2. Disconnect the RSS module connector.
3. Measure the resistance to ground on the Lift/Dive circuit at the RSS module connector terminal (harness side).

Is the resistance the same or less than the value specified?

10K ohms

Go to Step 9

Go to Step 7

7 | Measure the resistance of the Lift/Dive circuit between PCM connector C1 terminal 24 and the RSS module connector terminal (harness side). Is the resistance the same or less than the value specified? | 5 ohms | Go to Step 11 | Go to Step 10
8 | Repair short to voltage on CKT 1490. Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | --
9 | Repair the short to ground on CKT 1490. Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | --
10 | Repair the open in CKT 1490. Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | --

11

1. Check terminal contact at the RSS module.
2. Repair terminal contact if needed.

Was terminal contact repaired?

--

Go to Powertrain Control Module Diagnosis for Verify Repair

Perform RSS System Check

12

1. Check terminal contact at the PCM connector C1 terminal 24.
2. Repair terminal contact if needed.

Was terminal contact repaired?

--

Go to Powertrain Control Module Diagnosis for Verify Repair

Go to Step 13

13 | Replace the PCM. Refer to PCM Replacement/Programming . Is the replacement complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | --