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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Eldorado 🢒 Engine 🢒 Engine Controls - 4.6L 🢒 DTC P1633 Ignition 0 Switch Circuit

Refer to Engine Controls Schematics

PCM Power and Grounds


Object Number: 584716 Size: FS
Engine Controls Components
Information Sensors/Switches Description
MIL Control and DLC
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
PCM (BAT), A/C COMP, PARK/REV Fuses and A/C COMPRESSOR Relay
CRUISE, DIS, and PCM (IGN) Fuses
BATT 2 Fuse and Ignition Switch (2 of 2)
G102
 .

Circuit Description

The powertrain control module (PCM) receives three ignition inputs from the ignition switch: IGN 0, IGN 1, and CRANK Request. The PCM receives the IGN 0 input with the ignition switch in UNLOCK, and RUN. The PCM uses a class 2 ignition mode message, and the voltage input from two separate systems to test the IGN 0 circuit. If the PCM detects an improper IGN 0 input, DTC P1633 will set.

Conditions for Running the DTC

No Class 2 serial data circuit problem.

Conditions for Setting the DTC

The PCM detects an improper IGN 0 input.

Action Taken When the DTC Sets
    • The PCM will not illuminate the malfunction indicator lamp (MIL).
    • The PCM will store conditions which were present when the DTC set as Fail Records only.

Conditions for Clearing the DTC
    • The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • The DTC can be cleared by using the scan tool Clear DTC Information function.

Diagnostic Aids

If the condition is intermittent, refer the Intermittent Conditions in Symptoms.

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain On Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the IGN 0 display on the scan tool.

Does the IGN 0 scan tool display ON?

--

Go to Step 3

Go to Step 4

3

Observe the IGN 0 display while turning the ignition switch to the START position.

Does the IGN 0 display indicate OFF with the ignition switch in the START position?

--

Go to Diagnostic Aids

Go to Step 6

4
  1. Turn OFF the ignition.
  2. Disconnect the PCM connector.
  3. Connect test lamp between the IGN 0 circuit and ground.
  4. Turn ON the ignition.

Is the test lamp ON?

--

Go to Step 8

Go to Step 5

5
  1. Test the IGN 0 circuit for an open or poor connections at the ignition switch.
  2. If the condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 9

6
  1. Turn OFF the ignition (Leave the ignition switch OFF for this step).
  2. Disconnect the PCM connector.
  3. Connect test lamp between the IGN 0 circuit and ground.

Is the test lamp ON?

--

Go to Step 7

Go to Step 10

7
  1. Test the IGN 0 circuit and a short to voltage.
  2. If the condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 9

8

Inspect for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

If a condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 10

9

Replace the ignition switch. Refer to Steering Column Lock and Ignition Switch Cylinder Replacement - On Vehicle in Steering Wheel and Column - Tilt.

Is the action complete?

--

Go to Step 11

--

10

Important: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Is the action complete?

--

Go to Step 11

--

11
  1. Review and record the scan tool Fail Record data.
  2. Clear the DTC(s).
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the Specific DTC Information for DTC P1633 until the test runs.

Does the scan tool indicate that DTC P1633 passed?

--

System OK

Go to Step 2