GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The hybrid control module (HCM) provides a ground for the PWR MAINT Relay coil circuit. This DTC detects IGN1 relay/Power maintain relay stuck on or off.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2533 Ignition relay rationality fault

Conditions for Running the DTC

    • Ignition state = Run or Crank
    • Power maintain relay = ON and APM direction = 42 to 14
    • Power maintain relay = Off and Ignition state = Off

Conditions for Setting the DTC

    • HCM ignition state = Run Or Crank and Power Mode = Run or Crank and PCM state = Power Off or Extended Power Off.
    • Power Maintain relay = On and PCM state = Power Off or Extended Power Off
    • HCM ignition state = Accessory or Off and Power Mode = Accessory or Off and PCM state = Power Off or Extended Power Off.

Conditions for Clearing the DTC

    • A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
    • A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.

Step

Action

Value(s)

Yes

No

Schematic Reference: Starting and Charging Schematics

Connector End View Reference: Engine Electrical Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Install a scan tool.
  2. Turn the ignition ON, with the engine OFF.
  3. Observe the Ignition 1 Status parameter in the HCM data list.

Does the scan tool display ON?

--

Go to Step 3

Go to Ignition Relay Diagnosis

3

  1. Set the APO switch to Continuous.
  2. Observe the Power Maintain Relay parameter in the HCM data list

Does the scan tool display ON?

--

Go to Step 4

Go to Step 5

4

  1. Turn the ignition OFF.
  2. Disconnect the power maintain relay.
  3. Turn the ignition ON, with the engine OFF.
  4. Connect a test lamp between the battery positive voltage circuit of the power maintain relay coil and a good ground.

Does the test lamp illuminate?

--

Go to Step 5

Go to Step 10

5

  1. Connect a test lamp between the battery positive voltage circuit of the power maintain relay coil and the control circuit of the power maintain relay.
  2. With the scan tool, command the Power Maintain Relay special function ON?

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 6

6

Test the control circuit of the power maintain relay from the HCM for a short to ground, open or short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct condition?

--

Go to Step 14

Go to Step 8

7

Connect a test lamp between the battery positive voltage circuit of the power maintain switch circuit and a good ground.

Does the test lamp illuminate?

 

Go to Step 9

Go to Step 11

8

Inspect for poor connections at the harness connector of the HCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

 

Go to Step 14

Go to Step 13

9

Inspect for poor connections at the power maintain relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

 

Go to Step 14

Go to Step 12

10

Repair the open or short to ground in the power maintain relay coil circuit. Refer to Wiring Repairs .

Did you complete the repair?

 

Go to Step 14

--

11

Repair the open or short to ground in the switch circuit of the power maintain relay. Refer to Wiring Repairs .

Did you complete the repair?

 

Go to Step 14

--

12

Replace the power maintain relay. Refer to Relay Replacement .

Did you complete the replacement?

 

Go to Step 14

--

13

Replace the HCM. Refer to Control Module References for replacement, setup and programming.

Did you complete the replacement?

 

Go to Step 14

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14

  1. Review and record the scan tool Fail Records data.
  2. Clear any DTCs.
  3. Operate the vehicle within the Fail Records conditions as noted.
  4. Using a scan tool, monitor the Specific DTC info for this DTC.

Does the scan tool indicate that this DTC failed this ignition?

--

Go to Step 2

System OK