GM Service Manual Online
For 1990-2009 cars only

Object Number: 313521  Size: MF
Instrument Cluster and HUD Components
Cell 81: Brake, Fuel, Oil, Cruise, Volt and Airbag Indicators

Circuit Description

The instrument cluster monitors the fuel level directly from the fuel level sender on a discrete input. The fuel level sender has a resistance range from 40 ohms (below E) to 250 ohms (above F). The instrument cluster filters the raw fuel level data in order to display the data on the gauge. The instrument cluster has two filter modes.

One filter mode is a slow (heavy) filter. The vehicle uses the slow filter when the vehicle is not in PARK . The slow filter prevents fuel slosh from affecting the fuel gauge display.

The second filter mode is a fast (light) filter. The vehicle uses the fast filter when the vehicle is in PARK. The fast filter allows the fuel gauge display to respond quickly whenever the vehicle is refueling.

The instrument cluster also sends raw fuel level data to the PCM through the class 2 serial data line.

Conditions for Setting the DTC

DTC B0532 sets when the instrument cluster detects that the fuel input is less than 11 ohms for more than 2.5 seconds. This condition indicates that the circuit is shorted to ground.

Action Taken When the DTC Sets

When the DTC B0532 sets, the following events occur:

    • The instrument cluster moves the fuel gauge pointer to the lowest position below E.
    • The instrument cluster does not illuminate the low fuel LED indicator.
    • The instrument cluster sends a class 2 message to the PCM indicating the condition.

Diagnostic Aids

DTC B0532 is set as current only as long as the fault is occurring.

DTC B0532 is changed to a history status after the fault has stopped occurring.

DTC B0532 Fuel Level Sensor Input Shorted to Ground

Step

Action

Value(s)

Yes

No

1

Did you perform the Instrument Cluster Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

Inspect CKT 30 (PPL) for a short to ground.

Is the wiring OK?

--

Go to Step 4

Go to Step 3

3

Repair the short to ground.

Is the pepair complete?

--

Go to Diagnostic System Check - Instrument Cluster

--

4

Test for an intermal short of the fuel level sender.

Is the sender OK?

--

Go to Intermittents and Poor Connections Diagnosis

Go to Step 5

5

Replace the Fuel Level Sender.

Is the replacement complete?

--

Go to Diagnostic System Check - Instrument Cluster

--