DTC B2600 Daytime Running Lamp Circuit Malfunction. Oldsmobile Cutlass 1998

For 1990-2009 cars only

Makes 🢒 Oldsmobile 🢒 1998 🢒 Cutlass 🢒 DTC 🢒 DTC B2600 Daytime Running Lamp Circuit Malfunction

Refer to Headlights/Daytime Running Lights (DRL) Schematics .

Circuit Description

The daytime running lamps (DRL) are controlled by the body control module (BCM). The BCM grounds circuit 592 in order to energize the DRL relay coil. When the DRL relay energizes, ground is supplied to the low beam headlamps through the DRL resistor. Battery voltage is available at all times to the headlamps. The BCM monitors the low beam circuits to ensure that the DRLs are operating properly. If the BCM senses that the DRLs are not operating properly, DTC B2600 is set.

Conditions for Running the DTCs

•	The ignition switch is on.

•	The headlamp switch is off.

•	The park brake is unapplied.

•	The transaxle is in gear.

Conditions for Setting the DTC

One or more of the following conditions is/are present:

•	Circuit 592 is open.

•	Circuit 592 is shorted to battery.

•	Circuit 41 is open.

•	Circuit 640 is open.

•	Circuit 740 is open.

•	Circuit 1201 is open.

•	Circuit 589 is open

•	Circuit 1350 is open.

•	An open in the DRL resistor.

Action Taken When the DTC Sets

•	The BCM turns off the DRL relay control for the remainder of the ignition cycle.

•	The SERVICE VEHICLE SOON indicator lights.

•	The check gauges chime sounds.

Conditions for Clearing the DTC

•	A current DTC B2600 clears when the malfunction is no longer present and the ignition switch is cycled.

•	All BCM history codes clear after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles.

Diagnostic Aids

•	Diagnose all other DRL DTCs before DTC B2600.

•	An open headlamp bulb may set this DTC.

•	An open DRL resistor may set this DTC.

•	If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while wiggling the wiring and connectors. This may often cause the malfunction to appear.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

Listen for an audible click when the DRL relay operates. Command both the ON and OFF states. Repeat the commands as necessary.

Tests for voltage at the coil side of the DRL relay.

Verifies that the body control module is providing ground to the DRL relay.

Step	Action	Yes	No
1	Did you perform the Lighting Systems Diagnostic System Check?	Go to Step 2	Go to Body Control Module System Check
2	Inspect the HTR-A/C IGN fuse. Is the fuse open?	Go to Step 8	Go to Step 3
3	Inspect the RH HDLP fuse. Inspect the LH HDLP fuse. Is either fuse open?	Go to Step 10	Go to Step 4
4	Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the DRL relay ON and OFF. Does the DRL relay turn ON and OFF with each command?	Go to Step 12	Go to Step 5
5	Turn OFF the ignition. Disconnect the DRL relay. Turn ON the ignition, with the engine OFF. Probe the coil side feed circuit of the DRL relay with a test lamp that is connected to a good ground. Does the test lamp illuminate?	Go to Step 6	Go to Step 17
6	Connect a test lamp between the control circuit of the DRL relay connector and the coil side feed circuit of the DRL relay connector. With a scan tool, command the DRL relay ON and OFF . Does the test lamp turn ON and OFF with each command?	Go to Step 18	Go to Step 7
7	Test the control circuit of the DRL relay for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 20	Go to Step 15
8	Test the coil side feed circuit of the DRL relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 20	Go to Step 9
9	Replace the HTR-A/C IGN fuse. Did you complete the replacement?	Go to Intermittents and Poor Connections Diagnosis in Wiring Systems	--
10	Test the headlamp feed fcircuit or a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 20	Go to Step 11
11	Replace the blown fuse. Did you complete the replacement?	Go to Intermittents and Poor Connections Diagnosis in Wiring Systems	--
12	Test the ground feed circuit of the DRL relay and the DRL resistor for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 20	Go to Step 13
13	Test the headlamp feed circuits for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 20	Go to Step 14
14	Test circuit 1201 for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 20	Go to Step 15
15	Inspect for poor connections at the harness connector of the body control module. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 20	Go to Step 16
16	Replace the body control module. Refer to Body Control Module Replacement in Body Control System. Important: Perform the set up procedure for the body control module. Refer to Body Control Module (BCM) Programming/RPO Configuration . Did you complete the replacement?	Go to Step 20	--
17	Repair the coil side feed circuit of the DRL relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 20	--
18	Inspect for poor connections at the DRL relay. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 20	Go to Step 19
19	Replace the DRL relay. Did you complete the replacement?	Go to Step 20	--
20	Use the scan tool in order to clear the DTCs . Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?	Go to Step 2	System OK