P21CB Cadillac Code - Reductant Control Module Supply Voltage Low Voltage
Quick Answer
The selective catalytic reduction system reduces Oxides of Nitrogen (NOx) emissions by injecting a metered amount of reductant into the exhaust gas stream entering the selective catalytic reduction catalyst. Common causes include Faulty Reductant Control Module, Reductant Control Module harness is open or shorted, Reductant Control Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P21CB Cadillac indicates Reductant Control Module Supply Voltage Low Voltage.
- Common causes
- Common causes include Faulty Reductant Control Module, Reductant Control Module harness is open or shorted, Reductant Control Module circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P21CB Cadillac Description
The Diagnostic Trouble Code (DTC) will be set when the Reductant Control Module supply voltage is less than a calibrated value for greater than 5 s.
What are the Possible Causes of the DTC P21CB Cadillac?
- Faulty Reductant Control Module
- Reductant Control Module harness is open or shorted
- Reductant Control Module circuit poor electrical connection
How to Fix the DTC P21CB Cadillac?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P21CB Cadillac code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the P21CB Cadillac code?
Need more information on how to fix the P21CB Cadillac code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P21CB Cadillac code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P21CB Cadillac Code
1. What are the common symptoms of OBDII code P21CB in a Cadillac related to the Reductant Control Module Supply Voltage being low?
- Common symptoms include reduced engine performance, poor fuel economy, and potential issues with the vehicle's emissions system.
2. What are the possible causes of the Reductant Control Module Supply Voltage being low in a Cadillac triggering code P21CB?
- Potential causes may include a faulty reductant control module, damaged wiring or connectors, a weak battery, or issues with the vehicle's electrical system.
3. How can I diagnose the cause of OBDII code P21CB in my Cadillac related to the Reductant Control Module Supply Voltage?
- Diagnosing the issue typically involves using a diagnostic scanner to retrieve the fault codes, checking the voltage levels at the reductant control module, inspecting wiring and connectors for damage, and testing the battery and electrical system.
4. Are there any repair tips for addressing OBDII code P21CB in a Cadillac due to low Reductant Control Module Supply Voltage?
- Repair tips may include inspecting and repairing any damaged wiring or connectors, replacing the reductant control module if necessary, ensuring the battery is in good condition, and checking for any underlying issues with the vehicle's electrical components.
5. Can driving with OBDII code P21CB related to low Reductant Control Module Supply Voltage cause further damage to my Cadillac?
- Continuing to drive with this issue may lead to decreased fuel efficiency, potential damage to the vehicle's emissions system, and could eventually cause more severe engine performance problems if left unresolved.
6. How urgent is it to address OBDII code P21CB indicating low Reductant Control Module Supply Voltage in a Cadillac?
- It is recommended to address this issue promptly to prevent potential damage to the vehicle's emissions system and to ensure optimal engine performance and fuel efficiency.
7. Is it safe to continue driving my Cadillac with the check engine light on due to OBDII code P21CB?
- While it may be safe to drive in the short term, it is advisable to have the issue diagnosed and repaired as soon as possible to avoid any potential long-term damage to the vehicle.
8. Can a DIY enthusiast with basic automotive knowledge repair OBDII code P21CB caused by low Reductant Control Module Supply Voltage in a Cadillac?
- Depending on the underlying cause, some repairs related to this code may be within reach of a DIY enthusiast with basic automotive knowledge, such as checking and replacing fuses, connectors, or the reductant control module.
9. Will resetting the check engine light resolve OBDII code P21CB in a Cadillac related to low Reductant Control Module Supply Voltage?
- Resetting the check engine light without addressing the underlying issue will not solve the problem. It is crucial to diagnose the cause of the code and perform the necessary repairs to clear the fault code.
10. How much can I expect to pay for repairs related to OBDII code P21CB in a Cadillac due to low Reductant Control Module Supply Voltage?
- The cost of repairs can vary depending on the specific issue causing the code, the labor rates in your area, and the parts needed. It is recommended to obtain a diagnostic and repair estimate from a qualified mechanic.
Discuss the causes and fixes for P21CB Cadillac OBDII Code
Code P21CB Cadillac comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
