DTC P1599 Engine Stall or Near Stall Detected. Cadillac Concours 1997

For 1990-2009 cars
Engine Controls Components
Ignition Control (IC) Module
OBD II Symbol Description Notice
ESD Notice

### Circuit Description

The diagnostic test checks for an engine stall or near stall and sets DTC P1599 if a stall condition is detected. A partial start where engine RPM exceeds 400 RPM and the engine does not start, will also cause DTC P1599 to set. This DTC is designed to capture snapshot data of the stall condition.

### Conditions for Setting the DTC

#### Test Condition

Ignition ON.

#### Failure Conditions

• | Engine speed drops below 152 RPM after exceeding 400 RPM this ignition cycle.

• | No references pulses have been received for 0.75 second.

### Action Taken When the DTC Sets

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

• | The PCM will command a message to be displayed.

• | The PCM may record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records.

### Conditions for Clearing the Message/DTC

• | The PCM will turn the message OFF after one run and pass of the diagnostic test.

• | 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

Since many things can cause a stalling condition use the snapshot taken of DTC P1599 to compare the values taken when the DTC set to the Typical Scan Data Value table. Look for conditions that could have caused the stall and how long ago the stall occurred.

DTC P1599 may be set if the engine speed drops below 400 RPM, near stall, and then recovers.

### Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. If the customer does not have a stall complaint, ignore this DTC.

2. Check for other DTCs that may have caused a stalling condition to occur.

3. This DTC may set during a severe stumble or hesitation. If such is the case, diagnose the condition using the symptom diagnosis charts.

4. This step lists most of the possible causes of stalling arranged by subsystem.

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 | Is customer complaining of stalling? | -- | Go to Step 3 | Fault not present. Refer to Diagnostic Aids
3 | Are any other DTCs set? | -- | Go to DTCs that are set | Go to Step 4

4

1. Using a scan tool locate the Stall Data. This is the snapshot taken when the vehicle stalled and is not located with the Failure Records.
2. Check the MAP sensor display taken at the time this DTC was set.

Is the display more than the value specified?

95 kPa

Go to Step 5

Refer to Hesitation, Sag, Stumble diagnosis chart

5

1. One or more of the following systems may have caused the stalling condition.

• | Fuel System.

• | Idle Speed Control.

• | Emissions System.

• | Wiring and connections.

2. Perform Fuel System Check chart, check Test Descriptions.

Was a fault found and repaired?

--

Go to Powertrain Control Module Diagnosis for Verify Repair

Go to Step 6

6

1. Check for TCC improperly applied by a grounded TCC solenoid circuit or by transaxle hydraulic problems. Refer to Section 7 to diagnose.
2. Check ignition switch circuits for intermittent open to the PCM or ignition control module. Manipulate the key switch while driving to check for ignition switch intermittent or out of adjustment.
3. Check PCM ground and ignition control module ground.
4. Check for intermittent injector circuit operation.
5. Check the fuel PUMP ground for a loose or poor connection.

Did any of the checks above require a repair?

--

Go to Powertrain Control Module Diagnosis for Verify Repair

Refer to Diagnostic Aids