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1997 Chevy Astro Extended Cargo OBDII Code P1460 and P0420: Symptoms, Causes, and DIY Fix Guide

Model: 97 Chevy Astro Extended Cargo Fault Code: P0420 Posted: 2006-02-23 07:07

My 1997 Chevy Astro Extended Cargo starts and idles smoothly, with no issues at low speeds. However, when accelerating past 20-25 mph from a complete stop, the engine stutters and hesitates. The problem disappears when flooring the throttle. I've been consistently getting OBDII codes P1460 and P0420. According to my Haynes manual, P0420 indicates 'catalyst efficiency below threshold.' I'm not sure what P1460 means—some sources suggest it's related to a cooling fan control issue—but the van has never had an A/C system installed since 1997. The check engine light remains on constantly. I'm a mechanic trainee with limited budget and can't afford expensive dealership repairs that often don’t resolve underlying issues. Should I replace the catalytic converter and oxygen sensors? Is this the most cost-effective solution? The vehicle has 134,000 miles and was recently rebuilt about two months ago—only driven 75 miles before purchase, with an additional 300 miles since. It has always had a persistent check engine light. I suspect P1460 may be related to the A/C being disconnected at some point. The catalytic converter hasn't been replaced since 1997, and I haven't tested the oxygen sensors yet. Currently, I'm dealing with a serious oil leak—after adding one quart of oil, it all leaked out upon starting the engine—and the van is currently being towed to the shop for inspection. What are the most likely causes of this hesitation? Could faulty O2 sensors or a clogged catalytic converter be responsible? How can I diagnose these issues without spending much money?

Related fault codes

P0420

Comments (5)

Anonymous 2006-02-23 12:53

P1460 is typically interpreted as a cooling fan control fault. P0420 indicates the catalyst in bank 1 has reduced efficiency below threshold. Possible causes include a faulty catalytic converter, damaged wiring to oxygen sensors, or malfunctioning oxygen sensors themselves. This code suggests your shop might be stumped—does your vehicle's cooling fan operate normally? Jeff

Anonymous 2006-02-23 16:54

My cooling fans are working properly. I haven't tested the oxygen sensors yet. Could faulty O2 sensors cause hesitation when starting from a stop? This issue only occurs during acceleration, and the check engine light stays on continuously.

Anonymous 2006-02-24 07:06

A stumble at startup is more likely due to a restricted catalytic converter—though if fuel trim values are severely off, faulty oxygen sensors could be the culprit. However, I suspect the issue is less about O2 sensors and more related to backpressure or fuel mapping. Check your fuel trim values and verify whether the catalyst is clogged; a backpressure test using a vacuum gauge on the intake manifold can confirm this. Other factors—like ignition components, EGR valve operation—could also contribute. Does the hesitation coincide with the check engine light? What's the current mileage? Are all ignition system parts in good condition?

Anonymous 2006-02-27 07:46

The vehicle has 134,000 miles. It was rebuilt about two months ago and only driven 75 miles before I purchased it—now totaling 300 miles since. The check engine light has been on continuously since purchase. I believe P1460 may be caused by the A/C being disconnected at some point. The catalytic converter hasn't been replaced since 1997, and I haven’t tested the oxygen sensors yet. Currently, there's a severe oil leak—after adding one quart of oil, it all leaked out when starting the engine. The van is currently being towed to the shop for inspection so I can locate the leak and have my boss fix it.

Anonymous 2006-02-27 07:49

134,000 miles is relatively early for a full engine replacement unless the vehicle had significant prior wear. If there were ongoing issues like oil or coolant burning—common in GM vehicles—then the catalytic converter and/or oxygen sensors may have become contaminated over time. I hope your boss can assist you with diagnostics and repairs on this issue.