DTC B3887 or B3888
Diagnostic Instructions
DTC Descriptors
| DTC B3887 02: Trailer Left Turn Signal Circuit
Short to Ground |
| DTC B3887 04: Trailer Left Turn Signal Circuit
Open |
| DTC B3888 02: Trailer Right Turn Signal
Circuit Short to Ground |
| DTC B3888 04: Trailer Right Turn Signal
Circuit Open |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Trailer Left Turn Signal
|
3887 02
|
3887 04
|
-
|
-
|
Trailer Right Turn Signal
|
B3888 02
|
B3888 04
|
-
|
-
|
|
| |
Circuit/System Description
Ground is applied at all times to the turn signal/multifunction
switch. When the turn signal/multifunction switch is placed in
either the turn right or turn left position, ground is applied to
the body control module (BCM) through either the right turn or left
turn signal switch signal circuit. The BCM sends this message to
the trailer lighting converter. The trailer lighting converter then
applies a voltage to the appropriate trailer turn signal lamps
through there respective voltage supply circuits.
Conditions for Running the DTC
The appropriate trailer turn signal is active.
Conditions for Setting the DTC
B3887 02 or B3888 02
The trailer lighting converter detects a short to ground on the
control circuit.
B3887 04 or B3888 04
The trailer lighting converter detects an open control circuit.
Action Taken When the DTC Sets
The appropriate trailer turn signal lamp is inoperative.
Conditions for Clearing the DTC
The condition for setting the DTC is not longer present.
Reference Information
Schematic Reference
Trailer Connector/Provision Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, perform the appropriate Trailer Turn Signal Lamp
test. The appropriate trailer turn signal lamp should be
ON/OFF.
Circuit/System Testing
Trailer Turn Signal Lamp(s) Malfunction RPO VQ9
| 1. |
Ignition OFF, test for less
than 5 Ω between the X88 Trailer Connector terminal 3, 11, 13
and ground. |
| ⇒ |
If greater than the specified value, test the
appropriate ground circuit for an open/high resistance. |
| 2. |
Connect a test lamp between
the appropriate X88 Trailer Connector terminal listed below and
ground. |
| |
• |
X88 Trailer Connector terminal
1 |
| |
• |
X88 Trailer Connector terminal
4 |
| 3. |
Command the Trailer Turn
Signal Lamps test with a scan tool. The test lamp should turn ON
and OFF when changing between the commanded states. |
| ⇒ |
If the test lamp is always ON, test the signal
circuit for a short to voltage. If the circuit tests normal,
replace the K68 Trailer Lighting Control Module. |
| ⇒ |
If the test lamp is always OFF, test the signal
circuit for a short to ground or an open/high resistance. If the
circuits test normal, replace the K68 Trailer Lighting Control
Module. |
| 4. |
If all the circuits test
normal, test the appropriate turn signal lamp circuit at the
trailer. |
Trailer Turn Signal Lamp(s) Malfunction RPO D8G
| 1. |
Ignition OFF, remove the
appropriate bulb and inspect. |
| ⇒ |
If bulb is faulty, replace bulb. |
| 2. |
Ignition OFF, remove the of
the appropriate component listed below: |
| |
• |
E4LR Turn Signal Lamp - Left
Rear |
| |
• |
E4RR Turn Signal Lamp - Right
Rear |
| 3. |
Test for less than 5 Ω
between the ground circuit harness connector wiring color WH and
ground. |
| ⇒ |
If greater than the specified value, test the
appropriate ground circuit for an open/high resistance. |
| 4. |
Connect a test lamp between
the appropriate control circuit terminal listed below and
ground: |
| |
• |
E4LR Turn Signal Lamp - Left
Rear wiring color YE |
| |
• |
E4RR Turn Signal Lamp - Right
Rear wiring color BN |
| 5. |
Command the Trailer Turn
Signal Lamps test with a scan tool. The test lamp should turn ON
and OFF when changing between the commanded states. |
| ⇒ |
If the test lamp is always ON, test the signal
circuit for a short to voltage. If the circuit tests normal,
replace the K68 Trailer Lighting Control Module. |
| ⇒ |
If the test lamp is always OFF, test the signal
circuit for a short to ground or an open/high resistance. If the
circuits test normal, replace the K68 Trailer Lighting Control
Module. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
Control Module References for trailer lighting converter
replacement, setup and programming
|
