P2AE4: Intake Air O2 Sensor Pumping Current Circuit Low Bank 1

P2AE4 flags too low a level in the pumping current circuit belonging to the bank 1 intake sensor, usually a pump lead chafed through to ground or an internal short in the pump cell. Saab's 2010 9-5 gives a useful reference for the same wire on its exhaust probe: about 2.8 V on terminal 1 at ignition-on with the sensor unplugged, and its low code P2238 sets when the signal stays under 1.7 V for 3 s on overrun. Ford instead stores a grounded IP lead as P0131. No maker documents P2AE4 for an intake sensor. Because the ECM can no longer pump oxygen through the cell, it loses the value it compares with the zero point learned without EGR, and recirculation is reduced or switched off. P2AE3 is the open lead, P2AE5 the high side, P2AED bank 2.

Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.

Symptoms

• Check engine light on
• EGR reduced or switched off
• Possibly higher NOx at an emissions test

Most likely causes

• Pump current lead shorted to ground
• Internal short in the pump cell
• Sensor interface in the ECM faulty

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the wiring and connector of the sensor indicated
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Look for exhaust leaks
4. Check the signal in live data with the engine warm
5. Check the fuse and the heater resistance if the code mentions it
6. Replace the sensor if it has power and does not respond

Good to know

• Repair difficulty: medium
• It affects emissions.

What each character of P2AE4 means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• A: Hybrid or air and fuel
• E4: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2AE4?

Yes, you can normally drive in moderation, but get it repaired soon: you will use more fuel and the catalytic converter can be damaged over time.

What causes code P2AE4?

The most common causes are: pump current lead shorted to ground; internal short in the pump cell; sensor interface in the ECM faulty.

Related codes

• P2AE3Intake Air O2 Sensor Pumping Current Circuit Open Bank 1
• P2AE5Intake Air O2 Sensor Pumping Current Circuit High Bank 1
• P2AEDIntake Air O2 Sensor Pumping Current Circuit Low Bank 2
• P2AE1Intake Air O2 Sensor Pumping Current Trim Circuit Low Bank 1
• P2238O2 Sensor Positive Current Control Circuit Low (Bank 1 Sensor 1)

Sources

• saabwisonline.com: dtc p2237 p2239 p2243 p2251 or p2626
• newtonnet.co.uk: fordobd2012
• patents.google.com: en
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.