Air Bag Warning Light bulb harness is open or shorted
Air Bag Warning Light bulb circuit poor electrical connection
Faulty Restrain Control Module (RCM)
|How to Fix the B1870 Code?
Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
The cost to diagnose the B1870 code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
The air bag indicator is designed to illuminate for 6 (±2) seconds when the ignition switch is turned to the RUN position. This initial 6 seconds of illumination is considered normal operation and is called Prove-Out of the air bag indicator. The air bag indicator is then used to warn the driver that there is a fault in the air bag Supplemental Restraint System (SRS) .
The air bag Restrain Control Module (RCM) module monitors the air bag indicator for open and short to ground conditions. If the ECS detects an open or short to battery condition on the air bag indicator circuit, it will store a Diagnostic Trouble Code (DTC) B1870 in memory.
If the RCM detects an air bag indicator failure in addition to another SRS failure, the RCM will send a signal to the Generic Electronic Module (GEM) module to produce five sets of five tone bursts.
B1870 Code - Lamp Air Bag Warning Indicator Circuit Short To Battery
Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service
Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed,
it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.
Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.